TWI459698B - Frequency-conversion mode converter and regulated method thereof - Google Patents

Description

Frequency conversion mode converter and control method thereof

The invention relates to the field of switching power supplies, and in particular to a frequency conversion mode converter and a control method thereof.

Switching power converters are widely used in energy conversion for their high efficiency and energy saving. From chargers for portable electronic products such as mobile phones and MP3s, to home appliances such as TVs and refrigerators, to automotive electronics, base communication power supplies, to new energy technologies, and aerospace military technology.

EMI (Electro Magnetic Interference) is a type of interference that is more common in electronic circuits. Whether in the field of switching power supplies, in the field of integrated circuits or other electronic fields, how to effectively reduce EMI is an issue that electronics designers need to consider when designing circuits or systems.

Switching power converters can be divided into two categories according to different operating frequency variations: one is a fixed frequency mode converter and the other is a variable frequency mode converter. Both types of converters include two parts as shown in FIG. 1 and FIG. 2. The fixed-frequency mode converter includes a power stage circuit module 101 and a fixed-frequency signal level circuit module 102; and the variable-frequency mode converter includes a power stage circuit mode. Group 101 and variable frequency signal level circuit module 202.

Power stage circuit module 101 and fixed frequency signal of the switching power converter shown in FIG. 1 and FIG. The level circuit module 102 or the variable frequency signal level circuit module 202 forms a closed loop system, as shown in FIG. G(S) is a transfer function of the power stage circuit module, and H(S) is a transfer function of the fixed frequency signal level circuit module 102 or the variable frequency signal level circuit module 202. The R(S) signal is converted to C(S) via the transfer function G(S). As shown in FIG. 1 and FIG. 2, for the fixed-frequency mode converter and the variable-frequency mode converter, the power-level circuit modules 101 of the two may be the same, but the fixed-frequency signal-level circuit module 102 and the variable-frequency signal-level circuit module 202 may There is a difference. Referring to a fixed-frequency mode converter illustrated in FIG. 4, the fixed-frequency signal-level circuit module 102 of the fixed-frequency mode converter usually includes an oscillator capable of generating a fixed-frequency signal, and the oscillation frequency of the oscillator is systematic. The operating frequency is determined by the oscillation of Rt and Ct. Since the system operating frequency of the fixed-frequency mode converter is constant, by changing the effective values of Rt and Ct, the frequency-hopping in the fixed-frequency system can be easily realized, thereby reducing the EMI. In a fixed-frequency system, jitter can be achieved by shaking the oscillator. There are many ways to implement frequency hopping in other traditional fixed frequency systems, and this is no longer an example.

However, the variable frequency signal level circuit module 202 of the variable frequency mode converter generally does not include the oscillator 105 shown in FIG. The operating frequency of the variable frequency mode converter is determined by its input and output states. Taking the topology diagram of the flyback converter shown in FIG. 5 as an example, the difference between the variable frequency mode converter and the fixed frequency mode converter is further described. The signal level circuit module portion of the flyback converter circuit is not illustrated in FIG. 5. FIG. 5 mainly illustrates the power stage circuit module. The flyback converter circuit shown in Figure 5 can operate in either a fixed frequency mode, such as CCM (Current Continuous Mode); it can also operate in a variable frequency mode, such as DCMB (Current Critical Mode). The current of the flyback converter circuit operating in DCMB mode is shown in Figure 6. Therefore, it can be seen from the above-exemplified switching power converter that the same power circuit module can work in both the fixed frequency mode and the variable frequency mode. Under the formula, the hardware or control method of the signal level circuit module in the fixed frequency mode and the hardware or control method of the frequency conversion signal level circuit module in the frequency conversion mode may be different. Still taking the topology diagram of the flyback converter shown in Figure 5 as an example, please refer to Figure 7, where the operating frequency in the inverter mode changes with the load (ie, the output of the converter), In frequency mode, its operating frequency is fixed and will not be affected by load changes (ie, it will not change with output changes). Therefore, the variable frequency mode converter cannot be distinguished from the fixed frequency mode from the power level topology structure in some cases, but can be distinguished from the signal level circuit module or the control method.

Like the fixed-frequency mode converter, there is also a problem of EMI in the variable-frequency mode converter. The operating frequency of the variable-frequency mode converter varies with the input and output. The control of the variable-frequency mode converter is relatively complicated, and the vibration is added to the frequency conversion mode. Frequency function is more difficult. The traditional method is to add an EMI filter to the variable frequency mode converter to reduce EMI. This not only increases the cost, but also increases the size of the variable frequency mode converter.

Although the frequency converter is high in efficiency, it is widely used in some small and medium power switching power supply systems, but the EMI is poor. How to reduce EMI in the variable frequency mode converter, effectively reducing or avoiding the use of EMI filters is faced by those skilled in the art. problem.

The problem addressed by the present invention is to reduce EMI, reduce or avoid the use of EMI filters in variable frequency mode converters.

The problem solved by the present invention is also that frequency hopping is implemented in the variable frequency mode converter.

The problem solved by the present invention is also to reduce cost and volume.

A first aspect of the invention discloses a variable frequency mode converter, which operates in a variable frequency mode converter In the frequency conversion mode, the power level circuit module and the variable frequency signal level circuit module are included; the variable frequency signal level circuit module and the power level circuit module are electrically connected to form a closed loop circuit system. The variable frequency mode converter further includes a control unit, and the output of the control unit loads a continuously varying jitter signal in the variable frequency signal level circuit module, so that the operating frequency of the power stage circuit module controlled by the variable frequency signal level circuit module continuously changes.

The continuously varying jitter signal frequency is greater than the crossover frequency of the closed loop circuit system, thereby enabling the variable frequency signal level circuit to continuously change the operating frequency of the power stage circuit module.

In an embodiment of the variable frequency mode converter disclosed in the first aspect, the control unit is a jitter signal generator that outputs a continuously varying jitter signal to the variable frequency signal level circuit module. The variable frequency signal level circuit module includes a detection stage circuit and a control stage circuit. Therefore, the signal output by the control unit can be loaded into the control stage circuit or loaded into the detection stage circuit or loaded into the control stage circuit.

In an embodiment of the variable frequency mode converter disclosed in the first aspect, the regulating unit is a regulating component and a regulating component controller matched with the regulating component, and the regulating component is connected to the input detecting stage circuit in the detecting stage circuit. The parameter of the control element controller controlling the control element continuously changes over time such that the input detection stage circuit loads the continuously varying jitter signal.

According to a second aspect of the present invention, a variable frequency mode converter includes a power stage circuit module and a variable frequency signal level circuit module. The variable frequency signal level circuit module and the power level circuit module are electrically connected to form a closed loop circuit system, and the frequency conversion mode converter further comprises a control unit, the control unit is connected to the power level circuit module, and the control unit can change the power level circuit module Resonance parameters make the power stage circuit module work The frequency changes continuously. In an embodiment of the variable frequency mode converter disclosed in the third invention, the control unit includes at least one control component and a control component controller matched with the control component, the control component is connected to the power stage circuit module, and the control component controller The parameter values of the control regulatory elements vary continuously over time. The regulating component is a variable capacitor, a variable inductor or a variable capacitor and a variable inductor; and the regulating component controller is a controller for controlling the regulating component.

A third aspect of the present invention discloses a method for regulating a variable frequency mode converter, the frequency conversion mode converter comprising a power stage circuit module and a variable frequency signal level circuit module. The variable frequency signal level circuit module and the power stage circuit module are electrically connected to form a closed loop circuit system. The control method is: adding a control unit in the variable frequency mode converter, and using the control unit to load a continuously varying jitter signal in the signal input to the power stage circuit module of the variable frequency signal level circuit module, so that the frequency conversion mode converter The output signal is dithered to extend the operating frequency range of the variable frequency mode converter. The frequency of the continuously varying jitter signal is greater than the crossover frequency of the closed loop circuitry to achieve an extension of the operating frequency range of the variable frequency mode converter.

The technical effect of the invention is that EMI can be reduced or avoided in the variable frequency mode converter, and the EMI filter can also be effectively reduced or avoided. Frequency hopping is implemented in the variable frequency mode converter to average EMI energy and reduce EMI jitter peaks.

101‧‧‧Power level circuit module

102‧‧‧Fixed signal level circuit module

103‧‧‧Detection level circuit

104‧‧‧Control level circuit

105‧‧‧Oscillator

106‧‧‧Control unit

107‧‧‧jitter signal generator

202‧‧‧Variable signal level circuit module

1062‧‧‧Control circuit

301‧‧‧Electrical capacitor

302‧‧‧Transformer

303‧‧‧Rected diode

304‧‧‧Output electrolytic capacitor

305‧‧‧resistance

306‧‧‧Photocoupler

307‧‧‧Power switch tube

308‧‧‧Detection resistance

309‧‧‧Transistor

Fm‧‧‧resonance frequency

L‧‧‧Magnetic Inductance

Ci‧‧‧ parasitic capacitance

T‧‧‧ work cycle

Tosc‧‧‧Resonance time

Cs‧‧‧Resonant Capacitor

Ls‧‧‧Resonant Inductance

R(S), C(S)‧‧‧ signals

G(S), H(S)‧‧‧ transfer function

Rt‧‧‧Variable resistor

Ct, 1061‧‧‧ variable capacitor

Lt‧‧‧Variable Inductors

Io‧‧‧current source

R _cs ‧‧‧Detection resistance

I _{peak2 ‧‧‧peak} current

1 and 4 are schematic structural diagrams of a fixed-frequency mode converter; FIGS. 2, 8, 9, 11, 12, and 23 are schematic structural diagrams of a variable-frequency mode converter; and FIG. 3 is a schematic diagram of a self-control structure of a switching power supply converter; Figure 5, 13, 16, 17, 20 are the topology diagram of the flyback converter mode converter; Figure 6 is the current time relationship diagram of the flyback converter circuit operating in DCMB mode; Figure 7 is the fixed frequency mode converter and frequency conversion Schematic diagram of the relationship between the operating frequency of the mode converter and the load; Figure 10 is a Bode diagram of the closed-loop system shown in Figure 3; Figure 14 is a schematic diagram of the structure of the variable-frequency mode converter with BUCK as the topology; Figure 15 is the conversion of the conversion mode of BOOST to the topology Schematic diagram of the structure of the device; FIG. 18 is a schematic diagram of the BUCK topology of the variable frequency mode converter; FIG. 19 is a schematic diagram of the BOOST topology of the variable frequency mode converter; FIG. 21 is a frequency conversion mode converter of the waveformless mode generator of FIG. EMI conduction test diagram; Figure 22 is an EMI conduction test diagram when the jitter signal generator is a sine wave generator circuit in the technical scheme shown in Figure 17; Figure 24, 25, and 26 are flyback frequency conversion mode converter topologies Figure 27 is a schematic diagram of the effect of the variable resistance module on the on-time; Figures 28 and 29 are schematic diagrams of the inverter mode converter; Figures 30 and 31 are schematic diagrams of the flyback quasi-resonant control topology; Figure 32 is the flyback Schematic diagram of a quasi-resonant drain-source voltage waveform; FIG. 33 is a schematic diagram of an LLC resonant circuit of a variable frequency mode converter; FIG. 34 is a schematic diagram of a topology structure of a PFM control mode, FIG. 35 is a schematic structural diagram of a control unit; FIG. 36 is a schematic diagram of a quasi-resonant frequency conversion mode converter with a BUCK topology; FIG. 37 is a quasi-resonant frequency conversion with a BOOST topology. Schematic of the mode converter.

DETAILED DESCRIPTION OF THE INVENTION The present invention is described in detail below with reference to the accompanying drawings.

In order to effectively reduce EMI and avoid using EMI filters as much as possible, the main technical solution of the present invention is to implement frequency hopping in a variable frequency mode converter, so that the electromagnetic interference generated by the converter is spread over a wider frequency band, and the power supply is reduced in a certain frequency. The EMI peak generated by the frequency points can effectively prevent the electromagnetic interference generated by the converter from being seriously excessive in individual frequency bands.

The variable frequency mode converter has a relatively stable operating frequency when the input and output states are constant. At this time, the EMI has a high peak at the switching frequency and its multiple frequency. The invention actively adds a continuously varying jitter signal in the variable frequency mode converter, so that the operating frequency of the variable frequency mode converter is continuously changed, so that the electromagnetic interference generated by the variable frequency mode converter is spread over a wider frequency band. At the same time, the frequency-hopping of the variable-frequency mode converter needs to overcome the reduction of the continuously varying jitter signal due to the stability of the inverter mode converter itself, and realize the variable-frequency mode converter with relatively stable input and output. , the jitter of its working frequency. The variable frequency mode converter of the present invention is exemplified by a DC-DC power converter.

The invention includes a variable frequency mode converter as disclosed in both aspects. The variable frequency mode converter disclosed in the first aspect is configured to output a continuously varying jitter signal by setting a control unit. And loaded into the variable frequency signal level circuit module of the variable frequency mode converter, so that the operating frequency of the power stage circuit module controlled by the variable frequency signal level circuit module continuously changes. The variable frequency mode converter disclosed in the second aspect is to connect a control unit in the power stage circuit module of the variable frequency mode converter to change the resonance parameter of the power stage circuit module, so that the operating frequency of the power stage circuit module occurs. Continuous change. Figure 8 is a block diagram showing the structure of a variable frequency mode converter corresponding to the variable frequency mode converter disclosed in the first aspect. FIG. 9 is a schematic structural view of a variable frequency mode converter corresponding to the variable frequency mode converter disclosed in the second aspect. The variable frequency mode converter disclosed in the above two aspects changes the parameters affecting the operating frequency of the variable frequency mode converter by applying a continuously varying jitter signal at different positions of the variable frequency mode converter, thereby achieving continuous frequency jitter of the operating frequency.

The variable frequency mode converter disclosed in the first aspect has a requirement for a continuously varying jitter signal output by the control unit: the jitter signal is not an instantaneous jitter signal, and since the variable frequency mode converter is a closed loop circuit system, the instantaneous jitter signal cannot be realized. The operating frequency of the power stage circuit module changes continuously; in addition, when the added jitter signal is a continuously varying jitter signal, if the frequency of the jitter signal is lower than the crossing frequency of the closed loop system, it is easily eliminated by the closed loop circuit system itself, so regulation The frequency of the continuously varying jitter signal output by the unit needs to be greater than the crossing frequency of the closed loop circuit system, so that the operating frequency of the power stage circuit module can be continuously changed. The continuously varying jitter signal is a periodic or non-periodic voltage or current waveform whose amplitude can be fixed or varied. It should be noted that when the input and output of the variable frequency mode converter are relatively stable, the continuously varying frequency hopping signal will cause the output of the variable frequency mode converter to fluctuate within a certain range, in order to cope with such fluctuation, design The continuously varying jitter signal can be adjusted according to the actual demand for the output mode of the variable frequency mode. The magnitude of the output of the variable frequency mode converter is within the range allowed by the design requirements.

For the closed-loop system of the variable frequency mode converter as shown in FIG. 3, the definition of the crossing frequency is briefly described in conjunction with the Bode diagram shown in FIG. R(s) and C(s) are input and output, respectively, G(s) is the main circuit, and H(s) is the feedback control. In a loop system consisting of G(s) and H(s), the product of G(S) and H(S) represents the open-loop transfer function of the system. The frequency at which the Bode plot gain of the open-loop transfer function G(S)H(S) is 1 (or 0 dB) is called the crossing frequency, which is defined as the frequency at which the amplitude frequency crosses 0 dB. The phase on the phase-frequency curve corresponding to the crossover frequency reflects the relative stability of the loop system. The intersection of the curve shown in Fig. 10 and the abscissa is the crossing frequency point.

Various embodiments of the variable frequency mode converter disclosed in the first aspect are described in detail below.

Example 1

In the variable frequency mode converter, if the control signal in the link of the variable frequency signal level circuit module is continuously changed, the operating frequency of the power stage circuit module may be continuously changed. If the variable frequency signal level circuit module continuously loads the frequency hopping signal larger than the frequency converter mode crossover frequency, the operating frequency of the power stage circuit module will continuously change, thereby causing the operating frequency of the frequency conversion mode converter to be jittered.

FIG. 11 is a schematic structural diagram of a variable frequency mode converter. The control unit is implemented by a jitter signal generator 107. The jitter signal generator 107 outputs the continuously varying jitter signal to the variable frequency signal level circuit module 202. The dither signal generator 107 can be a signal generator that is common in the prior art. The continuously varying dither signal is loaded into the variable frequency signal level circuit module 202. The jitter signal generator 107 generates the continuous change The jitter signal changes the control signal outputted by the variable frequency signal level circuit module 202 to the power stage circuit module 101, thereby realizing the operating frequency jitter of the variable frequency mode converter. The frequency of the continuously varying jitter signal is greater than the crossing frequency of the closed loop circuitry of the variable frequency mode converter. The jitter signal generator 107 can be disposed at any position in the power stage circuit module or the variable frequency signal level circuit module.

Example 2

On the basis of the technical solution of FIG. 11, more specifically, the present invention discloses another technical solution, as shown in FIG.

The variable frequency signal level circuit module 202 includes a detection stage circuit and a control stage circuit. Taking the topology diagram of the flyback frequency conversion mode converter shown in FIG. 13 as an example, the power stage circuit module 101 includes an electrolytic capacitor Cbus301, a transformer 302, a rectifying diode D303, an output electrolytic capacitor C0 304, and a power switching tube 307. . The detection stage circuit includes a sense resistor Rcs308, a resistor 305 and an optocoupler 306, and the sense resistor Rcs308 is used for current sampling detection. The detection resistor Rcs308 belongs to the input detection stage circuit, the resistor 305 and the optocoupler 306 belong to the output detection stage circuit, and the output detection stage circuit detects the output of the power stage circuit module 101. The control stage circuit includes a drive unit and a feedback control circuit. The feedback control circuit receives the signal output feedback signal outputted by the optocoupler 306 to the driving device, and the driving device outputs the control signal to the power stage circuit module. The output signal of the dither signal generator 107 is loaded into a detection stage circuit, such as a load input detection stage circuit. Specifically, three circuit topologies are exemplified. As shown in FIGS. 13 to 15, the output of the jitter signal generator 107 is connected to one end of the detecting resistor Rcs308, and the continuously varying jitter signal generated by the jitter signal generator 107 is loaded to Input current detection of the detection stage circuit, thereby changing the size of the detection signal of the input detection stage circuit, so that the signal input from the input detection stage circuit to the control stage circuit is continuously dithered to realize the power level circuit module The impact of the 101 operating frequency.

In the circuit topology diagram of the flyback type variable frequency mode converter shown in FIG. 13, the continuously varying jitter signal generated by the jitter signal generator 107 includes a voltage or current waveform having a fixed or varying amplitude, which is periodic. Or non-periodic, the waveform includes sine waves, triangle waves, square waves, trapezoidal waves or superimposed waves of various waveforms. The continuously varying jitter signal is indirectly or directly loaded into the signal detected by the input detection stage by an adder, a multiplier, an amplifier, etc., such as a current sampling detection signal, thereby causing the signal value detected by the input detection stage to continuously change. .

Those skilled in the art will appreciate that the turn-on time of the power switch 307 of the variable frequency mode converter determines the operating frequency. When the jitter signal generator is not set, the power switch tube is turned off when the detection signal reaches a certain value. After the jitter signal generator is set, when the continuously varying jitter signal is added to reduce the detection signal, the frequency conversion mode is switched. The power switch tube of the device is also kept open until the size of the original detection signal reaches the size of the original detection signal, and the power switch tube is turned off. This increases the drive period of the variable frequency mode converter, reduces the drive frequency, and reduces the operating frequency of the variable frequency mode converter. When the continuously varying dither signal is added to increase the detection signal, the operating frequency of the variable frequency mode converter increases.

The magnitude of the waveform of the continuously varying jitter signal determines how much the detected signal value changes, which in turn affects how much the operating frequency changes. At the same time, when the frequency of the continuously varying jitter signal is greater than the crossing frequency of the closed-loop circuit system of the entire variable-frequency mode converter, the continuously varying jitter signal is not attenuated by the system of the variable-frequency mode converter itself, thereby enabling the variable-frequency mode converter. The operating frequency is continuously changed to achieve continuous jitter of the operating frequency of the variable frequency mode converter.

The method of realizing the frequency jitter by changing the size of the signal detected by the input detection stage circuit, for example, the size of the current sampling detection signal, can also be applied to the frequency conversion mode converter with BUCK and BOOST as the topology, please refer to FIG. 14 and FIG. The schematic diagrams of the inverter mode converters with BUCK and BOOST are topologies, and the parts of the variable frequency signal level circuit modules are not shown in Figs.

Rcs in FIGS. 14 and 15 are detection resistors, the jitter signal generator 107 is disposed at one end of the detection resistor, and the continuously varying jitter signal generated by the jitter signal generator 107 is added to the current sampling detection signal at the detection resistor Rcs, thereby The turn-on time of the power switch tube 407 is affected, thereby affecting the operating frequency of the entire circuit.

Example 3

Similar to FIG. 13, the present invention also discloses a technical solution, please refer to FIG. 16. Fig. 13 achieves continuous jitter of the operating frequency by directly changing the magnitude of the current detecting signal. Fig. 16 illustrates an embodiment in which the present invention adds a continuously varying jitter signal generated by the regulating unit to the output detecting stage circuit. Specifically, an embodiment in which the magnitude of the voltage detection signal of the output detection stage circuit is changed to realize the operation frequency jitter of the variable frequency mode converter is exemplified in the embodiment illustrated in FIG.

The variable frequency signal level circuit module includes a detection stage circuit and a control stage circuit. The power stage circuit module includes an electrolytic capacitor Cbus301, a transformer 302, a rectifying diode D303, an output electrolytic capacitor C0 304, and a power switch tube 307. The signal detection stage includes a sense resistor Rcs308, a resistor 305 and an optocoupler 306 for voltage sampling detection at the output of the variable frequency mode converter. The detecting resistor Rcs308 belongs to the input detecting stage circuit, and the resistor 305 and the photocoupler 306 belong to the output detecting stage circuit. The input detection stage circuit and the output detection stage circuit respectively detect the input and output of the power module, and output the signal to Control stage circuit. The control stage circuit includes a drive unit and a feedback control circuit. The feedback control circuit receives the optocoupler 306 to output a feedback signal to the driving device, and the driving device outputs a control signal to the power stage circuit module. In this embodiment, the control unit is the jitter signal generator 107. The output signal of the dither signal generator 107 is loaded into the detection stage circuit, specifically the output detection stage circuit, thereby causing the output detection stage circuit to input signal jitter to the control stage circuit. Specifically, the output signal of the jitter signal generator 107 is loaded into one end of the resistor 305, thereby affecting the voltage detection signal at the resistor 305 detected by the output detection stage.

In the circuit topology diagram of the flyback type variable frequency mode converter of FIG. 16, the continuously varying jitter signal generated by the jitter signal generator 107 includes a voltage or current waveform having a fixed or varying amplitude, which is periodic or non- Periodically, the waveform includes a sine wave, a triangular wave, a square wave, a trapezoidal wave, or a superimposed wave of various waveforms. The continuously varying jitter signal is indirectly or directly loaded into the voltage detection signal of the output detection stage circuit by an adder, a multiplier or an amplifier, thereby causing a change in the magnitude of the detection signal, for example, by an adder load, that is, a voltage detection The signal is superimposed with a continuously varying jitter signal.

The voltage detection signal loaded with the continuously varying jitter signal is sent to the optocoupler 306, which is isolated by the optocoupler to the feedback control circuit, thereby affecting the feedback signal output by the feedback control circuit. The feedback signal affects the turn-on time of the power switch tube in the power stage circuit module through the control signal outputted by the driving device, and the turn-on time of the power switch tube 307 determines the operating frequency of the variable frequency mode converter.

If the continuously varying jitter signal is added to increase the voltage detection signal detected by the output detection stage, the power switch tube turn-on time is increased, resulting in an increase in the drive period, and the drive frequency is decreased, and the operating frequency of the converter is also It becomes smaller. corresponding, If the continuously varying dither signal is added to cause the voltage detection signal detected by the output detection stage to decrease, and the drive period is reduced, the operating frequency of the converter is increased. The amplitude of the waveform of the continuously varying jitter signal generated by the jitter signal generator determines how much the detection signal changes, thereby affecting the frequency variation. When the frequency of the continuously varying jitter signal is greater than the crossing frequency of the inverter mode converter, the voltage detection signal can be continuously changed, so that the operating frequency of the variable frequency mode converter is continuously changed to achieve continuous frequency jitter.

This manner of loading the control unit 106 with the jitter signal generator into the output detection stage circuit can also be applied to the output detection stage of the variable frequency mode converter in a BUCK, BOOST, etc. topology.

Example 4

The control unit 106 can be disposed in the control stage circuit.

Figure 17 is a circuit topology diagram of a flyback type variable frequency mode converter. The basic structure is similar to that of Figures 13 and 16, and the control stage circuit includes a driving device and a feedback control circuit. The difference is that the continuously varying jitter signal generated by the jitter signal generator 107 is indirectly or directly loaded into the feedback signal outputted by the feedback control circuit by means of an adder, a multiplier or an amplifier, thereby causing the feedback signal to change. The continuously varying jitter signal includes a sine wave signal, a triangular wave, a square wave, a trapezoidal wave, or a superimposed wave of various waveforms. The amplitude of the continuously varying dither signal is fixed or varied, and the continuously varying dither signal can be a periodic or non-periodicly varying voltage or current waveform. The magnitude of the waveform of the continuously varying jitter signal determines how much the amount of change in the feedback signal is caused, thereby affecting the control signal output by the driving device to the power stage circuit module, so that the operation of the power stage circuit module changes. Continuously loading continuously varying jitter signals, The operating frequency of the power stage circuit module is continuously changed to achieve continuous jitter of the operating frequency of the variable frequency mode converter.

The frequency of the output signal of the jitter signal generator needs to be greater than the crossing frequency of the entire closed-loop circuit system of the frequency conversion mode converter, and the continuous jitter of the operating frequency of the frequency conversion mode converter is realized. The magnitude of the waveform of the continuously varying jitter signal is determined, and the amount of change of the feedback signal is determined, thereby affecting the change of the operating frequency. If the feedback signal is continuously changed, the operating frequency of the variable frequency mode converter will also change continuously, thereby achieving continuous jitter of the operating frequency.

In fact, the control unit 106 can be placed at various stages of the control stage circuit, i.e., the continuously varying dither signal can be loaded not only in the feedback signal but also in other signals of the control stage circuit.

The method of realizing frequency jitter by loading the continuously varying jitter signal generated by the control unit 106 into the signal output from the feedback control circuit of the control stage circuit to the driving device can also be applied to the frequency conversion mode converter with BUCK and BOOST as the topology. In, as shown in Figures 18 and 19. The signal level circuit module portions of Figures 18 and 19 are not shown.

The continuously varying jitter signal generated by the control unit 106 can also be loaded into the control signal output by the control stage circuit to the power stage circuit module, for example as shown in FIG. The continuously varying jitter signal output by the jitter signal generator 107 can be loaded into the signal output by the driver to the control terminal of the power switch 307 in the power stage circuit module. It can also be applied to the conversion of the conversion mode of Buck and Boost for the topology.

21 is an EMI conduction test diagram of the variable frequency mode converter of the jitter-free signal generator 107 of FIG. 17, in which two parallel regular lines are shown, and the upper one is on the EMI quasi-peak. Limit, the lower one is the upper limit of the EMI average, the cross indicates the quasi-peak at a certain frequency point, the plus sign indicates the average value at a certain frequency, and the larger the ordinate value indicates the worse the EMI. Considering the difference between the same type of variable frequency mode converters, in order to avoid the EMI exceeding the upper limit due to the normal difference of the variable frequency mode converter, it is generally required that the quasi-peak value and the average value have a certain distance margin from the respective upper limits.

Line 1 is the peak line, which can be used to obtain the quasi-peak at a certain frequency point; Line 2 is the EMI average line. It can be seen from Figure 21 that the operating frequency of the system is approximately fixed at 110 kHz, and the EMI energy at each multiple of the operating frequency is high. At 330kHz and 440kHz, the Average line frequency band is narrow, the peak value is sharp, and the margin is only about 3dB~4dB from the upper limit.

FIG. 22 is a EMI conduction test diagram when the jitter signal generator is a sine wave generator circuit in the technical scheme shown in FIG. 17.

It can be seen that the EMI energy is distributed over a relatively wide frequency band at each octave of the operating frequency, thereby dispersing the peak energy. The average value of the averaged line after homogenization is about 10 dB. It can be seen that the average value of EMI is significantly reduced, and the test result of the peak line is also improved. (The number 1 curve is the peak line, number 2 The curve is the average line).

Adding the control unit to other positions of the control stage circuit of the variable frequency signal level circuit module can also implement the frequency hopping function, and is not limited to the above embodiment.

Example 5

In addition to directly changing the size of the detection signal or the feedback signal, the operating frequency of the variable frequency mode converter can be changed by changing the size of the detection signal indirectly by controlling the magnitude of the detection resistance, as shown in FIG.

The variable frequency signal level circuit module 202 includes a detection stage circuit and a control stage circuit. The detection stage circuit includes an input detection stage circuit and an output detection stage circuit, and the regulation unit 106 is electrically connected to the input detection stage circuit.

More specifically, please refer to Figures 24, 25, and 26.

The detecting resistor Rcs308 belongs to the input detecting stage circuit, the regulating unit 106 is electrically connected to the detecting resistor Rcs308, and the current detecting signal is obtained from the detecting resistor Rcs308. The control unit 106 includes a regulatory element and a regulatory element controller that is matched to the regulatory element. The regulating component 106 can be a variable resistor whose resistance value changes with time under the control of the variable resistance controller matched with the variable resistor, thereby realizing the input detection signal of the input stage detecting circuit. Loads a continuously varying jitter signal.

Specifically, the variable resistor is a resistor Rt, and the sense resistor Rcs308 is connected in series or in parallel with the resistor Rt, as shown in FIG. The resistor Rt receives a control signal from the variable resistance controller. By setting the resistor Rt, the peak current flowing through the detecting resistor Rcs308 is changed, that is, the detection signal is changed, thereby converting the operating frequency of the mode converter.

More specifically, as shown in FIG. 26, the resistor Rt is implemented by a transistor 309 operating in a linear region, and the variable resistor controller 310 is a circuit module capable of outputting a varying voltage, which can output periodic or non-periodic changes. The voltage signal can be a sine wave, a triangular wave, a square wave, a trapezoidal wave, and a superimposed wave. Changing the base voltage loaded into the transistor allows the transistor to output a different impedance. The impedance of the triode is continuously controlled by the varying voltage signal output by the variable resistance controller. The impedance of the transistor 309 connected in parallel to the detecting resistor Rcs308 is continuously changed, so that the current detecting signal in the detecting resistor Rcs308 is continuously changed.

In the flyback topology, the primary peak current flowing through the power switch tube is related to the power switch tube conduction time. The larger the peak current is, the longer the power switch tube is turned on, the on time and the variable frequency mode converter work. Frequency related.

The voltage sampling signal Vcs across the detecting resistor Rcs is considered to be constant for a short period of several switching cycles, where Vcs=Ipeak*Rcs, and Ipeak is the peak current flowing through the detecting resistor Rcs. After the triode is connected in parallel, if the same Vcs sampling voltage value is to be obtained at both ends of the detecting resistor Rcs, the peak current flowing through the detecting resistor Rcs at this time is Ipeak2=Ipeak*RcsRt/(Rcs+Rt). It can be seen that the peak current Ipeak2 is an amount related to the Rt value, and the peak current Ipeak2 changes due to the change in Rt.

Since the peak current is larger, the on-time of the power switch tube is longer. Therefore, in the same Vcs, the power switch tube turn-on time Ton when there is no Rt resistance and the power switch tube turn-on time Ton2 after the parallel resistance value Rt are compared, because The detecting resistor R 308 in the overall input stage detecting circuit is equivalently smaller, and the connected resistor Rt changes linearly at any time, so that the primary peak current flowing through the power switching tube becomes larger, thereby making Ton2>Ton, see FIG. Figure 27 shows the effect of the variable resistance module on the on-time. Therefore, the above-mentioned exemplified control unit uses the input detection stage circuit in the variable frequency signal level circuit module to access the variable resistor which changes with time, so that the detection signal of the input detection stage circuit is loaded into a jitter continuously changing with time. The signal, which affects the continuous change of the on-time of the power switch, thereby achieving continuous jitter of the operating frequency of the variable frequency mode converter. The frequency of the jitter signal generated by the continuous change of the variable resistance over time needs to be greater than the frequency of the variable frequency mode converter, so that the continuously varying jitter signal realized by the variable resistance in the input detection stage circuit is not closed by the variable frequency mode converter itself. Attenuation is performed to achieve continuous variation of the operating frequency of the variable frequency mode converter, that is, continuous jitter of the operating frequency.

The jitter of the operating frequency can average the EMI energy, effectively reduce the EMI interference of the variable frequency mode converter, and reduce or avoid the use of the EMI filter in the conventional technology.

The above five embodiments are exemplified for the variable frequency mode converter of the first aspect of the present invention. However, the scope of protection of the present invention is not limited to the above embodiments, and is determined by the claims. For a part of the variable frequency mode converter, the load may affect the size of the crossing frequency, so the range of the crossing frequency can be determined according to the range of the load connected to the variable mode converter. The frequency of the continuously varying jitter signal generated by the control unit 106 is greater than the maximum crossing frequency in the range of the crossing frequency, so that the continuous jitter of the operating frequency can be realized in the load range of the load connected to the converter. Although the exemplary embodiments of the variable frequency mode converter of the first mode of the present invention are described by taking a DC-DC type variable frequency mode converter as an example, the variable frequency mode converter may also be AC-DC, DC- Other types of variable frequency mode converters such as AC and AC-AC.

The variable frequency mode converter disclosed in the second aspect will be described in detail below.

In addition to the above manner, by changing the parameters of the power stage circuit module by increasing the control unit, especially changing the parameters of the resonant element in the resonant state, the operating frequency of the variable frequency mode converter can be continuously changed to achieve frequency hopping.

FIG. 28 is a schematic structural diagram of a variable frequency mode converter including a power stage circuit module 101 and a variable frequency signal level circuit module 202 electrically connected to form a closed loop circuit system. The variable frequency mode converter further includes a regulating unit 106, and the regulating unit 106 is connected to the power circuit module 101. The control unit 106 changes the resonance parameter of the power stage circuit module to continuously change the operating frequency of the power stage circuit module. More specifically, please refer to FIG. 29, which is a schematic structural diagram of a variable frequency mode converter. The control unit 106 includes a control component and a control component component matched with the control component. Controller. The control component is connected to the power stage circuit module 101, and the control component controller controls the parameter value of the control component to change with time.

Example 1

On the basis of FIG. 29, please refer to FIG. 30 and FIG. 31, which are schematic diagrams of a flyback quasi-resonant control topology. The electrolytic capacitor 301, the transformer 302, the power switch tube 307, the rectifying diode 303, and the output electrolytic capacitor 304 constitute a power stage circuit module 101.

The control unit 106 is electrically connected to the drain of the power switch 307, the control component is a variable capacitor 1061, and the control component controller is a control circuit 1062. This variable capacitance Ct1061 may be a digital variable capacitor or a solid variable capacitor.

The working process of the technical solution shown in FIG. 31 is that when the power switch tube 307 is turned off, the energy transfer in the inductance of the transformer 302 is completed, and the secondary rectifying diode 303 is also turned off, the magnetizing inductance and the drain of the transformer are turned off. The parasitic capacitance begins to resonate. At this time, the drain-source voltage of the power switch 307 is detected. When the drain-source voltage is low, the power switch 307 is turned on (but not limited to the first detection. When the voltage is low, it can be turned on, which can effectively reduce the turn-on loss of the power switch tube and improve the conversion efficiency. The power switch tube is turned on at the bottom of the valley and is determined by the input voltage and load size. 32 is a schematic diagram showing the waveform of the drain-source voltage of the power switch in the flyback quasi-resonant variable frequency mode converter. Figure 32 illustrates the opening of the power switch tube at the second valley.

When resonance occurs, the resonance frequency fm is determined by the excitation inductance L and the drain parasitic capacitance Ci of the power switch tube 307, that is, fm=1/T.

Where T is the duty cycle. At this point, add a controllable at the drain of the power switch The variable capacitance of the capacitance can change the equivalent parasitic capacitance value Ci of the power switch tube, thereby changing the length of the entire resonance time Tosc by changing the resonance frequency fm, and finally changing the switching period. From the variable capacitor embodiment exemplified in FIG. 31, when the capacitance of the variable capacitor Ct is increased, Ci becomes large, and it is known from the formula (1) that the Tosc becomes long, the duty cycle becomes long, and the operating frequency decreases; When the capacitance of the capacitor Ct is decreased, Ci becomes small. It is known from the formula (1) that the Tosc becomes short, the duty cycle becomes short, and the operating frequency increases. If the equivalent capacitance value changes continuously, the operating frequency of the variable frequency mode converter will continuously change, thereby achieving frequency jitter.

The jitter of the operating frequency can average the EMI energy and effectively reduce the EMI of the variable frequency converter, thereby reducing or avoiding the use of EMI filters in the conventional technology.

Example 2

On the basis of FIG. 29, please refer to FIG. 33, which is a schematic diagram of an LLC resonant circuit of the variable frequency mode converter. The resonant circuit includes a resonant capacitor Cs and a resonant inductor Ls, all of which belong to a power stage circuit module.

In the series and parallel LLC resonant circuits, the switching frequency is the amount related to the resonant frequency, and the switching frequency is the operating frequency of the variable frequency mode converter.

The resonance frequency is related to the resonance parameter of the element participating in the resonance. Therefore, if the effective capacitance of the resonance capacitor Cs can be continuously changed, the resonance frequency is continuously changed, so that the operating frequency of the LLC converter is continuously changed.

The regulating element is a variable capacitor Ct connected in parallel to the resonant capacitor Cs, and the variable capacitor Ct can be a digital variable capacitor or a solid variable capacitor. The control element controller is a control circuit, and the resistance of the variable capacitor Ct is controlled by the control circuit to change with time. Figure 33 shows a series resonant LLC circuit, which is a variable frequency mode converter. Only the frequency conversion mode can be distinguished from the fixed frequency mode converter from the topology structure of its power stage circuit module. The topology diagram structure shown in FIG. 34 is different from the PWM control method of the flyback, boost, and step-down converters in other embodiments of the present invention, which is a PFM control mode. The working process of the series resonant LLC circuit shown in FIG. 33 is described. When the capacitance of the variable capacitor Ct is increased, the resonant frequency of the resonant circuit is reduced, and the operating frequency of the variable frequency mode converter is correspondingly reduced; On the contrary, when the capacitance value of the variable capacitor Ct is decreased, the resonance frequency is increased, and the switching frequency of the inverter mode converter is also increased. Therefore, by continuously controlling the change in the capacitance of the resonant capacitor Cs by the variable capacitor Ct, the switching frequency of the converter can be continuously changed, thereby achieving frequency jitter.

Example 3

Similar to the second embodiment, in addition to continuously changing the capacitance value of the resonant capacitor Cs, the purpose of changing the resonant frequency can be achieved by continuously changing the inductance value of the resonant inductor Ls, and the switching frequency of the converter is changed to achieve frequency hopping. FIG. 34 is a schematic diagram of an LLC resonant circuit of a variable frequency mode converter. The variable frequency mode converter has only the frequency conversion mode, and can be distinguished from the fixed frequency mode converter from the topology structure of its power stage circuit module. The topology diagram structure shown in FIG. 34 is different from the PWM control method of the flyback, boost, and step-down converters in other embodiments of the present invention, which is a PFM control mode.

In this embodiment, the regulating element is a variable inductor Lt connected in parallel to the resonant inductor Ls. The control element controller is a control circuit, and the inductance value of the variable inductance Lt is controlled by the control circuit to change with time. Figure 35 shows the structure of the control unit. The current source Io is the control circuit. The inductance of the variable inductor Lt is determined by the amount of magnetic flux passing through the core. The Io current source constantly changes the current in the conductor. To change the magnetic flux in the core, so that the inductance of Lt changes. The change in the inductance of the variable inductance Lt causes the resonant frequency to change and the operating frequency of the converter to change accordingly. As the resonant frequency increases, the switching frequency of the converter increases accordingly; the resonant frequency decreases and the switching frequency of the converter decreases accordingly. The inductance of the continuously varying variable inductance Lt eventually causes the operating frequency of the LLC converter to continuously change, achieving continuous jitter of the frequency.

Example 4

The regulating element can include a combination of a variable capacitor and a variable inductor. The regulation component controller controls the parameter values of the variable capacitor and the variable inductor to change with time.

For example, the variable inductance Lt shown in Fig. 34 and the corresponding control circuit can be provided in the circuit shown in Fig. 33.

Example 5

The method of changing the parameters of the resonant element in the power stage circuit module can also be applied to the quasi-resonant frequency conversion mode converter with BUCK and BOOST as the topologies, as shown in Figs. 36 and 37, the principle is to change the resonance. The cycle affects the power switching frequency.

The technical solution of the above two methods further includes various modifications. For example, the control unit 106 can be simultaneously applied to the power stage circuit module and the variable frequency signal level circuit module in accordance with any of the foregoing embodiments to achieve stable input and output. A frequency conversion mode converter with frequency jitter.

Based on the above-mentioned variable frequency mode converter disclosed in the two aspects of the present invention, the third party of the present invention also discloses a control method of the frequency conversion mode converter, and the control method is: The variable frequency mode converter comprises a power stage circuit module and a variable frequency signal level circuit module. The variable frequency signal level circuit module and the power stage circuit module are electrically connected to form a closed loop circuit system. The control method is: adding a control unit in the variable frequency mode converter, and using the control unit to load a continuously varying jitter signal in the signal input to the power stage circuit module of the variable frequency signal level circuit module, so as to convert the frequency conversion mode The output signal of the device is dithered to extend the operating frequency range of the variable frequency mode converter. The frequency of the continuously varying jitter signal is greater than the crossover frequency of the closed loop circuitry to achieve an extension of the operating frequency range of the variable frequency mode converter. A continuously varying dither signal is a periodic or non-periodic voltage or current waveform of fixed or varying amplitude. The control unit uses a jitter signal generator to input the continuously varying jitter signal generated by the jitter signal generator to the frequency conversion signal level circuit module, thereby realizing the adjustment of the signal input from the frequency conversion signal level circuit module to the power level circuit module. The variable frequency signal level circuit module comprises an input detection stage circuit and a control stage circuit, and the input detection stage circuit outputs a signal to the control stage circuit, and the control unit can adopt a control element and a control element controller matched with the control element, and the control element is connected The input detection stage circuit is controlled by the control element controller to control the parameter of the control element to change continuously with time to load the continuously varying jitter signal to the signal output from the input detection stage circuit to the control stage circuit.

These control methods can be used in various variable frequency mode converters such as current critical mode and discontinuous mode, but are not limited thereto.

The present invention reduces EMI, reduces or avoids the use of EMI filters in variable frequency mode converters. The continuous frequency-hopping is realized in the variable-frequency mode converter to average the EMI energy, effectively solving the problem of high EMI peak in the middle and low frequency bands, reducing the cost, and reducing the volume.

Various modifications may be made to the above without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is therefore not limited by the description, but by the scope of the claims.

<AlEx><AlEx>

101‧‧‧Power level circuit module

106‧‧‧Control unit

202‧‧‧Variable signal level circuit module

Claims (20)

A variable frequency mode converter, wherein the variable frequency mode converter operates in a frequency conversion mode, comprising a power stage circuit module and a frequency conversion signal level circuit module, wherein the variable frequency signal level circuit module is electrically connected with the power level circuit module a closed-loop circuit system, the variable-frequency mode converter further includes a control unit, wherein an output of the control unit loads a continuously varying jitter signal in the variable-frequency signal level circuit module, so that the variable-frequency signal-level circuit module controls the The operating frequency of the power stage circuit module continuously changes, and the frequency of the continuously varying jitter signal is greater than the crossing frequency of the closed loop circuit system. The variable frequency mode converter according to claim 1, wherein the control unit is a jitter signal generator that outputs the continuously varying jitter signal to the variable frequency signal level circuit module. The variable frequency mode converter according to claim 2, wherein the variable frequency signal level circuit module comprises a detection stage circuit and a control stage circuit, wherein the detection stage circuit detects the power stage circuit module and outputs a signal to the control a stage circuit, the control stage circuit outputs a signal to the power stage circuit module, and an output signal of the jitter signal generator is loaded into the detection stage circuit. The variable frequency mode converter according to claim 3, wherein the detection stage circuit comprises an input detection stage circuit and an output detection stage circuit, and an output signal of the jitter signal generator is loaded into the input detection stage circuit, so that The signal outputted to the control stage circuit by the input detection stage circuit is continuously dithered, and the output detection stage circuit detects the output of the power stage circuit module. The variable frequency mode converter described in claim 3, the detection stage circuit package An input detection stage circuit and an output detection stage circuit, wherein an output signal of the jitter signal generator is loaded into the output detection stage circuit, so that the signal outputted to the control stage circuit by the output detection stage circuit is continuously jittered, and the input detection stage A circuit detects an input of the power stage circuit module. The variable frequency mode converter according to claim 2, wherein the variable frequency signal level circuit module comprises a detection stage circuit and a control stage circuit, wherein the detection stage circuit detects the power stage circuit module and outputs a signal to the control The control circuit outputs a signal to the power stage circuit module, and the output signal of the jitter signal generator is loaded into the control stage circuit, so that the signal outputted by the control stage circuit to the power stage circuit module is continuously jittered. The variable frequency mode converter according to claim 6, wherein the control stage circuit comprises a feedback control circuit and a driving device, and the feedback control circuit receives the signal output by the detection stage circuit and outputs a signal to the driving device, The output signal of the jitter signal generator is loaded into the output of the feedback control circuit. The variable frequency mode converter according to claim 1, wherein the variable frequency signal level circuit module comprises a detection stage circuit and a control stage circuit, and the detection stage circuit comprises an input detection stage circuit and an output detection stage circuit. The control unit is electrically coupled to the input detection stage circuit. The variable frequency mode converter according to claim 8 , wherein the regulating unit is a regulating component and a regulating component controller matched with the regulating component, the regulating component is connected to the input detecting stage circuit, and the regulating component is The controller controls the parameter values of the control component to continuously change over time such that the input detection stage circuit loads the continuously varying jitter signal. The variable frequency mode converter according to claim 9, wherein the regulating component is a variable resistor, and the regulating component controller is a variable resistance controller. The variable frequency mode converter according to claim 1, wherein the continuously varying jitter signal is a periodic or aperiodic voltage or a current waveform having a fixed or varying amplitude. A control method for a frequency conversion mode converter, the frequency conversion mode converter comprises a power stage circuit module and a frequency conversion signal level circuit module, wherein the frequency conversion signal level circuit module and the power level circuit module are electrically connected to form a closed loop circuit The control method is: adding a control unit to the variable frequency mode converter, and using the control unit to load a continuously varying jitter signal on the signal input to the power stage circuit module of the variable frequency signal level circuit module, The output signal of the variable frequency mode converter is dithered to extend the operating frequency range of the variable frequency mode converter, and the continuously varying jitter signal frequency is greater than the crossover frequency of the closed loop circuit system. The control method according to claim 12, wherein the control unit uses a jitter signal generator to load the continuously varying jitter signal generated by the jitter signal generator into the variable frequency signal level circuit module. The control method according to claim 12, wherein the variable frequency signal level circuit module comprises an input detection stage circuit and a control stage circuit, wherein the input detection stage circuit outputs a signal to the control stage circuit, and the control unit adopts a control unit a regulating component and a regulating component controller matched with the regulating component, the regulating component is connected to the input detecting stage circuit, and the regulating component controller is controlled to continuously change the parameter of the regulating component to form an output of the input detecting stage circuit The continuously varying jitter signal is loaded onto the signal to the control stage circuit. The control method according to claim 12, wherein the continuously varying jitter signal is a periodic or aperiodic voltage or a current waveform having a fixed or varying amplitude. A variable frequency mode converter includes a power stage circuit module and a variable frequency signal level circuit module, wherein the variable frequency signal level circuit module is electrically connected with the power level circuit module a closed-loop circuit system, the variable-frequency mode converter further includes a control unit, the control unit is connected to the power stage circuit module, and the control unit can change a resonance parameter of the power stage circuit module to make the power level circuit module work The frequency changes continuously. The control unit includes at least one control component and a control component controller matched with the control component, and the control component is connected to the power stage circuit module, and the control component is connected to the power conversion circuit module. The controller controls the parameter values of the regulatory component to continuously change over time. The variable frequency mode converter according to claim 17, wherein the control component is a variable capacitor, and the variable capacitor is connected to the power circuit module, and the control component controller is a variable capacitance controller. The variable frequency mode converter according to claim 17, wherein the control component is a variable inductor, and the variable inductor is connected to the power circuit module, and the control component controller is a variable inductance control. Device. The variable frequency mode converter according to claim 17, wherein the control component is a combination of a variable capacitor and a variable inductor, and the control component controller controls the variable capacitor and/or the variable inductor The parameter values change continuously with time.