WO2018081918A1 - Switching power supply circuit and switching power supply current detection method - Google Patents

Abstract

A switching power supply circuit (100). The switching power supply circuit (100) comprises: a switching power supply control circuit (101), a load switching circuit (102) and a load current detection circuit (103), wherein the load switching circuit (102) comprises a target load; the switching power supply control circuit (101) comprises a power supply load; the switching power supply control circuit (101) is connected to the load switching circuit (102); the load current detection circuit (103) is connected to the load switching circuit (102); the load switching circuit (102) is used to incorporate the target load into the power supply load; the load current detection circuit (103) is used to detect a voltage value corresponding to the target load ; the switching power supply control circuit (101) is used to detect a first detection current value and a second detection current value; the switching power supply control circuit (101) is further used to calculate a current value corresponding to the target load according to the voltage value corresponding to the target load, and adjust the current value corresponding to the target load to a target current value; and the switching power supply control circuit (101) is further used to determine that a difference value between the second detection current value and the first detection current value is a detection value corresponding to the target current value.

Description

Switching power supply circuit and switching power supply current detecting method Technical field

The invention relates to the field of electronics, and in particular to a switching power supply circuit and a switching power supply current detecting method.

Background technique

Power consumption is a very important indicator for smart phones. Due to the high power conversion efficiency of switching power supply circuits, it has been widely used in power management circuits of smart phones. In actual use, the user expects to accurately obtain the current consumption of each switching power supply load, and provide data support for system power management.

In the prior art, the detection of the switching power supply current is generally performed by measuring the conduction voltage drop of the switching tubes of the respective switching power supplies, and calculating the current consumption of the switching power supply load according to the conduction impedance of the switching tubes.

Since the impedance of the switch is affected by the operating voltage and the temperature factor is large when the switch is turned on, the detection accuracy of this method is poor.

Summary of the invention

The embodiment of the invention provides a switching power supply circuit and a switching power supply current detecting method, which can reduce the detection error and improve the accuracy of the current detection.

In view of this, the first aspect of the present invention provides a switching power supply circuit including: a switching power supply control circuit, a load switching circuit, and a load current detecting circuit; the load switching circuit includes a target load; and the switching power supply control circuit Including the power load;

The switching power supply control circuit is connected to the load switching circuit; the load current detecting circuit is connected to the load switching circuit;

The load switching circuit is used to integrate the target load into the power load;

The load current detecting circuit is configured to detect a voltage value corresponding to the target load;

The switching power supply control circuit is configured to detect the first detection current value and the second detection current value, and the first detection current value is a current value corresponding to the switching power supply circuit when the power load is in a sleep state and the target load is in a high resistance state, and the second detection current is The value is a current value corresponding to the switching power supply circuit when the power load is in a sleep state and the current value corresponding to the target load is equal to the target current value;

The switching power supply control circuit is further configured to calculate a current value corresponding to the target load according to the voltage value corresponding to the target load, and adjust the current value corresponding to the target load to the target current value;

The switching power supply control circuit is further configured to determine a difference between the second detected current value and the first detected current value as a detected value corresponding to the target current value.

It should be noted that, in the embodiment of the present invention, the power load refers to the load in the original switching power supply circuit, and the target load is a high-precision load in the newly added load switching circuit, and the target load is connected in parallel with the power load.

Embodiments of the present invention provide a switching power supply circuit including a switching power supply control circuit, a load switching circuit, and a load current detecting circuit, wherein the load switching circuit includes a target load, and the switching power supply control circuit includes a power load, a load switching circuit connection, and a switching power supply. The control circuit and the load current detecting circuit are connected, the load switching circuit combines the target load into the power load, the load current detecting circuit detects the voltage value corresponding to the target load, and the switching power supply control circuit calculates the current value according to the voltage value of the target load, and The current value is adjusted to the target current value, and the recorded first detection current value and the second detection current value, that is, the current value corresponding to the switching power supply circuit and the current corresponding to the target load when the power load is in the sleep state and the target load is in the high resistance state When the value is equal to the target current value, the current value corresponding to the switching power supply circuit, the difference between the two is used as the detection value corresponding to the target current value. The embodiment of the invention integrates a high-precision target load on the basis of the original switching power supply circuit, replaces the original power load with a high-precision target load, and increases a high-precision load current detecting circuit, and the data detected by the circuit For reference, the data detected by the original switching power supply circuit is calibrated to reduce the detection error and improve the accuracy of the current detection.

With reference to the first aspect of the embodiments of the present invention, in a first implementation manner of the first aspect of the embodiments, the load switching circuit further includes a digital-to-analog converter DAC, an NMOS transistor, and a serial peripheral interface SPI;

The switching power supply control circuit and the load current detecting circuit are connected to the load switching circuit through the SPI;

One end of the DAC is connected to the SPI, the other end of the DAC is connected to the gate of the NMOS transistor, the drain of the NMOS transistor is connected to the target load, and the source of the NMOS transistor is grounded;

The switching power supply control circuit is also used to control the output voltage of the DAC, the output voltage is used to control the gate voltage of the NMOS transistor, the gate voltage is used to adjust the on-resistance of the NMOS transistor, and the on-resistance is used to adjust the current of the target load. value.

The embodiment of the invention provides a specific composition of the load switching circuit, which improves the achievability of the solution.

In a second implementation manner of the first aspect of the embodiment of the present invention, the load switching circuit further includes a sustain level resistor, and the level resistor is used for the NMOS. The transistor maintains a fixed level, one end of the level resistor is maintained connected to the gate of the NMOS transistor, and the other end of the level resistor is grounded.

Embodiments of the present invention provide a manner of maintaining a fixed level of an NMPS transistor in a load switching circuit, which improves the achievability of the solution.

With reference to the first aspect of the embodiments of the present invention, in a third implementation manner of the first aspect of the embodiments, the load current detecting circuit includes: a differential amplifying circuit, a first inverse proportional amplifying circuit, a gain adjusting circuit, and voltage following a circuit, a second inverse proportional amplification circuit, and an analog to digital converter ADC;

The input end of the differential amplifying circuit is connected to the target load, and the output end of the differential amplifying circuit is connected to the first inverse proportional amplifying circuit and the gain adjusting circuit;

The voltage follower circuit is connected to the first inverse proportional amplification circuit and the second reverse proportional amplification circuit;

The amplification ratio corresponding to the differential amplification circuit is 1:1; the amplification ratio corresponding to the second direction proportional amplification circuit is 1:1;

The first inverse proportional amplification circuit is configured to amplify the first output voltage of the differential amplification circuit, and the amplification ratio corresponding to the first inverse proportional amplification circuit is a target value;

a voltage follower circuit for buffering the first output voltage;

a gain adjustment circuit for adjusting a target value;

The ADC is used for sampling the output voltage of the second inverse proportional amplification circuit and the output voltage of the gain adjustment circuit, and the output voltage of the second inverse proportional amplification circuit is used for determining the voltage value corresponding to the target load, and the output of the gain adjustment circuit The terminal voltage is the adjustment factor of the target value.

The load current detecting circuit in the embodiment of the invention processes the voltage of the target load through a plurality of amplifying circuits, thereby reducing the influence of noise, temperature and the like on the voltage detection, and improving the detection precision.

In a fourth implementation manner of the first aspect of the embodiment of the present invention, the differential amplifying circuit includes a first operational amplifier A ₁ a second operational amplifier A ₂ , a first resistor R ₁ , a second resistor R ₂ , a third resistor R ₃ , a fourth resistor R ₄ , a fifth resistor R _{5 ,} and a PMOS transistor T ₂ ; the gain adjustment circuit includes a third operational amplifier A ₃ , R ₅ and T ₂ ; the voltage follower circuit includes a fourth operational amplifier A ₄ ; the second inverse proportional amplification circuit includes a fifth operational amplifier A ₅ , a sixth resistor R ₆ , a seventh resistor R ₇ and an eighth resistor R ₈ ;

A ₁ positive input end connected to the target load, the inverting input of A ₁ is connected to the other end of the target load, an output end ₂ is A ₁ R & lt termination, R _2, A the other end of the reverse input ₂ and R ₃ is an end side, the other end of R ₃ R _4, one end, the other end of the output terminal R ₄ a _2, a ₂ forward end of the input end of R _1, R ₁ is other end of the end ;

The inverting terminal of the reference voltage of A _3, A ₃ positive input end the output terminal of A _1, A ₃ output termination gate of T _2, a drain contact between the T ₃ R ₂ and R ₄ the intermediate node, T ₂ source electrode connected to one end of R _5, R ₅ other end of the terminal;

A ₄ forward input end of the output terminal of A _2, A _4, an inverting input end of the output terminal A _4;

One ends inverting terminal R A ₅ R ₇ and _8, the other end of the output terminal A ₄ R _7, the other end of the output terminal ₅ A R _8, the positive input terminal A of ₅ end R _6, R is other end of the end portion _6;

One end of the ADC is connected to the output of A _{5 and} the output of A ₃ , and the other end of the ADC is connected to the load switching circuit.

Embodiments of the present invention provide a specific structure of a load current detecting circuit, which improves the achievability of the solution.

With reference to the fourth implementation manner of the first aspect of the embodiment of the present invention, in the fifth implementation manner of the first aspect of the embodiment, the accuracy of R ₁ to R ₈ is one percent.

With reference to the first aspect of the embodiments of the present invention, the first to fifth implementation manners of the first aspect, in the sixth implementation manner of the embodiment of the present invention, the accuracy of the target load is one percent.

With reference to the first aspect of the embodiment of the present invention, the first to fifth implementation manners of the first aspect, in the seventh implementation manner of the embodiment of the present invention, the resistance of the target load is 0.5 ohm.

A second aspect of the embodiments of the present invention provides a power supply current detecting method, the method comprising:

The switching power supply circuit first determines the current value to be calibrated, that is, the target current value. The switching power supply circuit sets the target load to a high-impedance state, and sets the power load to a sleep state, and records the current value corresponding to the switching power supply circuit at this time, that is, the first current value. Then, the switching power supply circuit sets the target load to the working state, and detects the voltage value corresponding to the target load at this time, and calculates the current value corresponding to the target load according to the voltage value. When the current value corresponding to the target load is not equal to the target current value, the switching power supply circuit adjusts the current value corresponding to the target load to the target current value; when the current value corresponding to the target load is equal to the target current value, the switching power supply circuit records the detection at this time. The current value corresponding to the switching power supply circuit, that is, the second detected current value. Finally, the switching power supply circuit compares the difference between the second detected current value and the first detected current value The detection value corresponding to the target current value, that is, when the switching power supply circuit detects the current value of the switching power supply circuit as the difference, the actual current value of the corresponding switching power supply circuit is the target value.

Embodiments of the present invention provide a switching power supply circuit including a switching power supply control circuit, a load switching circuit, and a load current detecting circuit, wherein the load switching circuit includes a target load, and the switching power supply control circuit includes a power load, a load switching circuit connection, and a switching power supply. The control circuit and the load current detecting circuit are connected, the load switching circuit combines the target load into the power load, the load current detecting circuit detects the voltage value corresponding to the target load, and the switching power supply control circuit calculates the current value according to the voltage value of the target load, and The current value is adjusted to the target current value, and the recorded first detection current value and the second detection current value, that is, the current value corresponding to the switching power supply circuit and the current corresponding to the target load when the power load is in the sleep state and the target load is in the high resistance state When the value is equal to the target current value, the current value corresponding to the switching power supply circuit, the difference between the two is used as the detection value corresponding to the target current value. The embodiment of the invention integrates a high-precision target load on the basis of the original switching power supply circuit, replaces the original power load with a high-precision target load, and increases a high-precision load current detecting circuit, and the data detected by the circuit For reference, the data detected by the original switching power supply circuit is calibrated to reduce the detection error and improve the accuracy of the current detection.

With reference to the second aspect of the embodiments of the present invention, in a first implementation manner of the second aspect of the embodiment, the switching power supply circuit determines that a difference between the second detected current value and the first detected current value is a target current value. After the value is detected, the switching power supply circuit sets the target load to a high-impedance state and sets the power load to the active state.

In the embodiment of the present invention, after the calibration of the current value to be calibrated is completed, the target load can be set to a high-impedance state, which can avoid the influence on the switching power supply control circuit.

It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

Embodiments of the present invention provide a switching power supply circuit including a switching power supply control circuit, a load switching circuit, and a load current detecting circuit, wherein the load switching circuit includes a target load, and the switching power supply control circuit includes a power load, a load switching circuit connection, and a switching power supply. The control circuit and the load current detecting circuit are connected, the load switching circuit combines the target load into the power load, the load current detecting circuit detects the voltage value corresponding to the target load, and the switching power supply control circuit calculates the current value according to the voltage value of the target load, and The current value is adjusted to the target current value, and the recorded first detection current value and the second detection current value, that is, the power load is in a sleep state and the target load is in a high resistance state, the switching power supply circuit corresponds to The current value corresponding to the target load and the current value corresponding to the target current value are equal to the current value corresponding to the switching power supply circuit, and the difference between the two is used as the detection value corresponding to the target current value. The embodiment of the invention integrates a high-precision target load on the basis of the original switching power supply circuit, replaces the original power load with a high-precision target load, and increases a high-precision load current detecting circuit, and the data detected by the circuit For reference, the data detected by the original switching power supply circuit is calibrated to reduce the detection error and improve the accuracy of the current detection.

DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present invention, Those skilled in the art can also obtain other drawings according to these drawings without paying any creative work.

1 is a schematic diagram of an embodiment of a switching power supply circuit in an embodiment of the present invention;

2 is a schematic diagram of an embodiment of a load switching circuit in a switching power supply circuit according to an embodiment of the present invention;

3 is a schematic diagram of an embodiment of a load current detecting circuit in a switching power supply circuit according to an embodiment of the present invention;

4 is a schematic diagram of an embodiment of a method for detecting a switching power supply current in an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by a person skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

The terms "first", "second", "third", "fourth", etc. (if present) in the specification and claims of the present invention and the above figures are used to distinguish similar objects without being used for Describe a specific order or order. It is to be understood that the data so used may be interchanged as appropriate, such that the embodiments of the invention described herein can be implemented, for example, in a sequence other than those illustrated or described herein. In addition, the terms "comprises" and "comprises" and "the" and "the" are intended to cover a non-exclusive inclusion, for example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to Those steps or units, but may include those that are not clearly listed or Other steps or units inherent to these processes, methods, products or equipment.

It should be understood that the switching power supply circuit in the embodiment of the present invention is based on the prior art switching power supply circuit, and the related functional circuit is added and the function of the original switching power supply circuit is adaptively improved. In order to better understand the switching power supply circuit in the embodiment of the present invention, the switching power supply circuit in the prior art is introduced below. The switching power supply circuit is roughly composed of a main circuit, a control circuit, a detection circuit, and an auxiliary power supply.

1, the main circuit

Inrush current limiting: Limits the inrush current on the input side of the power supply.

Input filter: Its function is to filter the clutter in the grid and to prevent the clutter generated by the machine from feeding back to the grid.

Rectification and filtering: directly rectify the grid AC power to a smoother DC.

Inverter: The rectified DC power is changed to high frequency AC, which is the core part of the high frequency switching power supply.

Output rectification and filtering: Provides a stable and reliable DC power supply according to the load requirements.

2, the control circuit

On the one hand, sampling from the output, comparing with the set value, then controlling the inverter, changing its pulse width or pulse frequency to make the output stable, on the other hand, according to the data provided by the test circuit, the circuit is identified by the protection circuit. The control circuit performs various protection measures on the power supply.

3, detection circuit

Provides various parameters and various meter data in operation in the protection circuit.

4, auxiliary power supply

Software (remote) startup of the power supply, power supply for protection circuits and control circuits (chips such as PWM).

Based on the above background, an embodiment of the present invention provides a switching power supply circuit and a switching power supply current detecting method, which can reduce detection errors and improve current detection accuracy.

Referring to FIG. 1, an embodiment of a switching power supply circuit in an embodiment of the present invention, a switching power supply circuit 100, a switching power supply control circuit 101, a load switching circuit 102, and a load current detecting circuit 103;

Wherein, the load switching circuit 102 includes a target load; the switching power supply control circuit 101 includes a power load;

The switching power supply control circuit 101 is connected to the load switching circuit 102, and the load current detecting circuit 103 is connected to the load switching circuit 102;

The load switching circuit 102 is configured to integrate the target load into the power load;

The load current detecting circuit 103 is configured to detect a voltage value corresponding to the target load;

The switching power supply control circuit 101 is configured to detect a first detection current value and a second detection current value, wherein the first detection current value is a current corresponding to the switching power supply circuit 100 when the power supply load 1011 is in a sleep state and the target load is in a high resistance state. a value, the second detection current value is a current value corresponding to the switching power supply circuit 100 when the power load 1011 is in a sleep state and the current value corresponding to the target load is equal to the target current value;

The switching power supply control circuit 101 is further configured to calculate a current value corresponding to the target load according to the voltage value corresponding to the target load, and adjust a current value corresponding to the target load to the target current value;

The switching power supply control circuit 101 is further configured to determine a difference between the second detected current value and the first detected current value as a detected value corresponding to the target current value.

In the embodiment of the present invention, the switching power supply control circuit 101 first sets the power supply load 1011 to a sleep state, adjusts the target load to a high resistance state, detects and records the current value corresponding to the power supply circuit 100 at this time, that is, the first detected current value, and then switches. The power control circuit 101 adjusts the target load to be in a non-high impedance state, and at the same time, the switching power supply control circuit 101 controls the load current detecting circuit 103 to detect the voltage value corresponding to the target load, and then acquires the voltage value according to the voltage value and the target. Calculating the current value corresponding to the target load, and determining whether the current value is equal to the target current value. If equal, detecting and recording the current value corresponding to the power supply circuit 100 at this time, that is, the second detected current value, if not equal to Then, the target load is adjusted again so that the current value corresponding to the power supply circuit 100 is equal to the target current value. Finally, the switching power supply control circuit 101 uses the difference between the second detected current value and the first detected current value as the detected value corresponding to the target current value, that is, when the switching power supply control circuit detects that the current value of the power supply circuit 100 is the second detection. When the current value is different from the first detected current value, the actual current value of the corresponding power supply circuit 100 is the target current value.

It should be noted that, in the embodiment of the present invention, the power load 1011 refers to the load in the original switching power supply circuit, the target load is the high-precision load in the newly added load switching circuit 102, and the target load is connected in parallel with the power load 1011.

Embodiments of the present invention provide a switching power supply circuit including a switching power supply control circuit, and load cutting The circuit and the load current detecting circuit, wherein the load switching circuit comprises a target load, the switching power supply control circuit comprises a power load, the load switching circuit connection is connected with the switching power supply control circuit and the load current detecting circuit, and the load switching circuit integrates the target load into the power load The load current detecting circuit detects the voltage value corresponding to the target load, and the switching power supply control circuit calculates the current value according to the voltage value of the target load, and adjusts the current value to the target current value, and records the first detected current value and the second value. Detecting the current value, that is, when the power load is in the sleep state and the target load is in the high resistance state, the current value corresponding to the switching power supply circuit and the current value corresponding to the target load are equal to the target current value, and the current value corresponding to the switching power supply circuit is between The difference is used as the detection value corresponding to the target current value. The embodiment of the invention integrates a high-precision target load on the basis of the original switching power supply circuit, replaces the original power load with a high-precision target load, and increases a high-precision load current detecting circuit, and the data detected by the circuit For reference, the data detected by the original switching power supply circuit is calibrated to reduce the detection error and improve the accuracy of the current detection.

The load switching circuit can be configured in various manners according to the embodiment corresponding to FIG. 1 . The load switching circuit in the embodiment of the present invention is described below as an example. Referring to FIG. 2 , the load switching circuit in the embodiment of the present invention is described. A schematic diagram of a structure of a load switching circuit 102 in the embodiment of the present invention includes: a target load R _x , a digital to analog converter (DAC), and an N-type metal oxide semiconductor (N-Metal-Oxide-Semiconductor, NMOS) transistor T ₁ and Serial Peripheral Interface (SPI);

The SPI is used to connect with the switching power supply control circuit and the load current detecting circuit;

One end of the DAC is connected to the SPI, the other end is connected to the gate of the NMOS transistor, and the drain of the NMOS transistor is connected to the target load R _x , and the source is connected to the ground end;

Structure of the load circuit 102 is switched on, the gate voltage of the embodiment of the present invention, the switching power supply control circuit 101 also controls the output voltage of the DAC, the output terminal voltage for controlling the gate voltage of NMOS transistor T _1, ie, It is used to adjust the on-resistance of the NMOS transistor T ₁ for adjusting the current value of the target load R _x . That is to say, the switching power supply control circuit 101 realizes the adjustment of the current value of the target load by controlling the output voltage of the DAC.

Specifically, when the output voltage of the DAC is 0 volts, the NMOS transistor T _{1 is} turned off, the target load R _x has no current flowing, that is, the corresponding current value is 0; when the output voltage of the DAC is greater than the turn-on voltage of the NMOS transistor T ₁ The NMOS transistor T _{1 is} saturated and turned on, and the on-resistance is less than 20 milliohms. At this time, the current flowing through the target load R _x is determined by the resistance of the target load; when the voltage output from the DAC is between 0 volts and the turn-on voltage, The on-resistance of the NMOS transistor T ₁ varies from 20 milliohms to several hundred kilo ohms.

Alternatively, the load may further comprise the switching circuit 102 maintains the level of the resistor R _0, maintains the level of the resistor R _{0. 1} to maintain a fixed level for the NMOS transistor T, which maintains the level of the resistor R ₀ is connected to one end of the NMOS transistor T The gate of ₁ is connected to the ground at the other end.

It should be noted that, in the embodiment of the present invention, the resistance of the target load may be 0.5 ohms or other resistance values, which is not limited herein. The target load is a high-precision load, and the accuracy may be 1%, or It is another value, and is not limited here. The resistance of the level resistor can be 47K ohms, and can also be other resistance values, which is not limited herein.

The embodiment of the invention provides a specific structure of a load switching circuit, which improves the achievability of the solution.

Based on the embodiment corresponding to FIG. 1 above, the load current detecting circuit can have various structures. The load current detecting circuit in the embodiment of the present invention is described below as an example. Referring to FIG. 3, one of the load current detecting circuits is shown. Schematic diagram of the structure, the load current detecting circuit 103 in the embodiment of the present invention includes: a differential amplifying circuit 1031, a first inverse proportional amplifying circuit 1032, a gain adjusting circuit 1033, a voltage following circuit 1034, a second inverse proportional amplifying circuit 1035, and a modulus Converter (Analog-to-Digital Converter, ADC);

The input end of the differential amplifying circuit 1031 is connected to the target load R _x , and the output end of the differential amplifying circuit is connected to the first inverse proportional amplifying circuit 1032 and the gain adjusting circuit 1033 ;

The voltage follower circuit 1034 is connected to the first inverse proportional amplification circuit 1032 and the second inverse proportional amplification circuit 1035;

The amplification ratios of the differential amplifying circuit 1031 and the second inverse proportional amplifying circuit 1035 are both 1:1, which are used to reduce the influence of temperature, noise and the like on the circuit.

The first inverse proportional amplifying circuit 1032 is configured to amplify the first output voltage of the differential amplifying circuit 1031, and the corresponding scaling ratio of the first inverse proportional amplifying circuit 1032 is a target value;

Voltage follower circuit 1034 is configured to buffer the first output voltage;

The gain adjustment circuit 1033 is configured to adjust the target value;

The ADC is used to sample the output voltage of the second inverse proportional amplification circuit 1035 and the output voltage of the gain adjustment circuit 1033, wherein the output voltage of the second inverse proportional amplification circuit 1035 is used to determine the voltage corresponding to the target load R _x . The value, the output voltage of the gain adjustment circuit 1033 is used as an adjustment factor of the target value.

Specifically, the differential amplifying circuit 1031 includes a first operational amplifier A ₁ , and the first inverse proportional amplifying circuit includes 1032 including a second operational amplifier A ₂ , a first resistor R ₁ , a second resistor R ₂ , and a third resistor R ₃ . a fourth resistor R ₄ , a fifth resistor R ₅ and a P-channel transistor O ₂ transistor; the gain adjustment circuit 1033 includes third operational amplifiers A ₃ , R ₅ and T ₂ ; The voltage follower circuit 1034 includes a fourth operational amplifier A ₄ ; the second inverse proportional amplification 1035 circuit includes a fifth operational amplifier A ₅ , a sixth resistor R ₆ , a seventh resistor R ₇ and an eighth resistor R ₈ ;

A ₁ positive input end connected to the target load, the inverting input of A ₁ is connected to the other end of the target load, an output end ₂ is A ₁ R & lt termination, R _2, A the other end of the reverse input ₂ and R ₃ is an end side, the other end of R ₃ R _4, one end, the other end of the output terminal R ₄ a _2, a ₂ forward end of the input end of R _1, R ₁ is other end of the end ;

The inverting terminal of the reference voltage of A _3, A ₃ positive input end the output terminal of A _1, A ₃ output termination gate of T _2, a drain contact between the T ₃ R ₂ and R ₄ the intermediate node, T ₂ source electrode connected to one end of R _5, R ₅ other end of the terminal;

A ₄ forward input end of the output terminal of A _2, A _4, an inverting input end of the output terminal A _4;

One ends inverting terminal R A ₅ R ₇ and _8, the other end of the output terminal A ₄ R _7, the other end of the output terminal ₅ A R _8, the positive input terminal A of ₅ end R _6, R is other end of the end portion _6;

One end of the ADC is connected to the output of A _{5 and} the output of A ₃ , and the other end of the ADC is connected to the load switching circuit.

Based on the above circuit connection, the amplification ratio corresponding to the first inverse proportional amplification circuit 1032 is a target value.

Where R _T2 is the impedance of T ₂ . When V ₁ <V _ref , V ₃ is high level and T _{2 is} off, then the target value is

When V ₁ <V _ref , when V ₃ is low level, T _{2 is} saturated and turned on. Since the impedance is on the order of milli ohms when T ₂ saturation is turned on, the target value is

V ₁ is the output voltage of A ₁ , V ₃ is the input voltage of A ₃ , and V _ref is the reference voltage.

It should be noted that in the embodiment of the present invention, R ₁ to R ₈ are high-precision resistors, and the corresponding precision may be 1% or other values, which is not limited herein. The resistance value of R ₁ to R ₈ is generally on the order of K ohms, and is specifically set according to its action in the circuit, which is not limited herein.

It should be understood that the above structural composition is only one example, and the differential amplifying circuit 1031, the first inverse proportional amplifying circuit 1032, the gain adjusting circuit 1033, the voltage following circuit 1034, and the second inverse proportional amplifying circuit 1035 may also be combined by other components. The composition is not limited herein.

The detection accuracy of the load current detecting circuit 103 in the embodiment of the present invention is determined by the parameters of the ADC, the resistance values of R ₁ to R ₈ , and the resistance of R _x . The detection accuracy of the load current detecting circuit 103 in the embodiment of the present invention is described below with a specific example:

R ₁ = R ₃ = R ₄ = 10Kohm, R ₂ = 20Kohm, R ₅ = 1.25Kohm, V _ref = 50mV, ADC bit width 12 bits, accuracy 1/4096, input range 0 to 0 in the flow detection circuit 103 4.2V with a resolution of 1.02mV. The target load R _x = 0.5 ohm, the power supply load is in the range of 1A to 1 mA, and the output voltage of the switching power supply circuit to be detected is 1.0V.

When the current flowing through R _x is less than 100 mA, the voltage drop is less than 50 mV (ie, V ₁ <V _ref ), and A _{3 is} output low (ie, V ₃ is low), then the amplification ratio of A ₂ (ie, the target) Value) is

When the current flowing through R _x is greater than 100 mA, the voltage drop is greater than 50 mV (ie, V ₁ >V _ref ), and A _{3 is} output high (ie, V ₃ is high), then the amplification ratio of A ₂ (ie, the target) Value) is

That is to say, when the current flowing through R _x is greater than 100 mA, the output voltage of A ₅ , which is obtained by sampling by the ADC, is the voltage value corresponding to R _x , and the resolution of the ADC is 1.02 mV, that is, the current accuracy that can be detected is 2.04. mA.

When the current flowing through R _x is less than 100 mA, the output voltage of A ₅ obtained by sampling the ADC is five times the voltage value corresponding to R _x , and the resolution of the ADC is 1.02 mV, that is, the current accuracy that can be detected is 0.41 mA. .

Since R _x = 0.5 ohm, the output voltage of the switching power supply circuit is 1.0 V, so the maximum detectable current is 2 A, that is, in the range of 100 mA and 2 A, the current detection accuracy is 2.04 mA, which is about 2%. The current detection accuracy is 0.41 mA in the range of 0 to 100 mA.

The embodiments of the present invention provide several high-precision load current detecting circuits, which improve the achievability of the solution.

The switching power supply circuit in the embodiment of the present invention is described above. The power supply current detecting method in the embodiment of the present invention is described below. Referring to FIG. 4, an embodiment of the switching power supply current detecting method in the embodiment of the present invention includes:

401. The switching power supply circuit determines a target current value.

In the embodiment of the invention, the switching power supply circuit is composed of a switching power supply control circuit, a load switching circuit and a load current detecting circuit. When the switching power supply circuit needs to calibrate the detected current value, the switching power supply control circuit first determines the current to be calibrated. Value, the target current value.

402. The switching power supply circuit sets the target load to a high resistance state, sets the power load to a sleep state, and records a first detection current value corresponding to the switching power supply circuit;

After determining the target current value, the switching power supply control circuit adjusts the target load in the load switching circuit to a high-impedance state, and at the same time, sets the power load in the switching power supply control circuit to a sleep state, and detects and records the detected switching power supply circuit at this time. The corresponding current value, that is, the first detected current value.

403. The switching power supply circuit sets the target load to an operating state, and detects a voltage value corresponding to the target load.

After the first detection current value is recorded, the switching power supply control circuit adjusts the target load in the load switching circuit to a non-high resistance state, that is, sets it to an operating state. When the target load is in the working state, the switching power supply control circuit controls the load current detecting circuit to detect the voltage value corresponding to the target load. Specifically, the load current detecting circuit is a high-precision detecting circuit, and the detected voltage value has high precision, and the specific precision value is related to its circuit composition.

404. The switching power supply circuit calculates a current value corresponding to the target load according to the voltage value.

The switching power supply control circuit obtains the voltage value detected by the load current detecting circuit, and calculates a current value corresponding to the target load according to the voltage value and the resistance value of the target load.

405, the switching power supply circuit determines whether the current value corresponding to the target load is equal to the target current value, if not, proceed to step 406, and if so, proceed to step 407;

406, the switching power supply circuit adjusts the current value corresponding to the target load to the target current value, and step 407;

When the current value corresponding to the target load is not equal to the target current value, the switching power supply control circuit adjusts the current value corresponding to the target load to the target current value. Specifically, the switching power supply control circuit can adjust the current value of the target load by adjusting the impedance of the target load, and can also be used in other manners, which is not limited herein.

407. The switching power supply circuit records a second detection current value corresponding to the switching power supply circuit;

When the current value corresponding to the target load is equal to the target current value, the switching power supply control circuit records the current value corresponding to the detected switching power supply circuit at this time, that is, the second detected current value.

408. The switching power supply circuit determines that a difference between the second detected current value and the first detected current value is a detected value corresponding to the target current value.

The switching power supply control circuit calculates a difference between the second detected current value and the first detected current value, and uses the difference as the detected value corresponding to the target current value, that is, when the switching power supply control circuit detects the current value of the power supply circuit When the difference is made, the actual current value of the corresponding power supply circuit is the target current value.

It should be noted that the switching power supply circuit determines that the difference between the second detection current value and the first detection current value is a detection value corresponding to the target current value, that is, after the calibration of the target current value is completed, the target load may be set to a high resistance state. The power load is set to the working state. Since the target load is in parallel with the power load and the target load can be in a high-impedance state after the calibration is completed, the normal operation of the power load is not affected. After the calibration of the target current value is completed, the switching current supply circuit can continue to calibrate the next current value, and can perform other operations, which is not limited herein.

Embodiments of the present invention provide a switching power supply circuit including a switching power supply control circuit, a load switching circuit, and a load current detecting circuit, wherein the load switching circuit includes a target load, and the switching power supply control circuit includes a power load, a load switching circuit connection, and a switching power supply. The control circuit and the load current detecting circuit are connected, the load switching circuit combines the target load into the power load, the load current detecting circuit detects the voltage value corresponding to the target load, and the switching power supply control circuit calculates the current value according to the voltage value of the target load, and The current value is adjusted to the target current value, and the recorded first detection current value and the second detection current value, that is, the power load is in a sleep state and the target load is in a high resistance state, the switching power supply circuit corresponds to The current value corresponding to the target load and the current value corresponding to the target current value are equal to the current value corresponding to the switching power supply circuit, and the difference between the two is used as the detection value corresponding to the target current value. The embodiment of the invention integrates a high-precision target load on the basis of the original switching power supply circuit, replaces the original power load with a high-precision target load, and increases a high-precision load current detecting circuit, and the data detected by the circuit For reference, the data detected by the original switching power supply circuit is calibrated to reduce the detection error and improve the accuracy of the current detection.

For ease of understanding, the switching power supply current detecting method in the embodiment of the present invention is described in an actual application scenario:

The output voltage of the switching power supply circuit to be detected is 1.0V, the maximum load current of the power supply is 2A, the target load resistance is 0.5 ohm, and 500mA is the current to be calibrated. When calibration is required, the power load is put into a sleep state, and the target load is set to a high-impedance state. At this time, the power load consumes power on the order of 1 to 2 mA, and the switching power supply control circuit records the current of the switching power supply circuit detected at this time. Data 1.2 mA (first sensed current value). The switching power supply control circuit sets the target load to the working state, and controls the load current detecting circuit to detect the voltage value corresponding to the target load, and calculates the current value of the target load according to the voltage value and the resistance value of the target load, if the current value is not equal to 500 mA , the impedance of the target load is adjusted until the current value corresponding to the target load is 500 mA. Since the 500 mA is the current calibrated by the ADC in the load current detecting circuit, the switching power supply control circuit records the current data of the switching power supply circuit detected at this time 510 mA. (Second detection current value), based on 510-1.2=508.8mA, this data is the calibrated 500mA load data, and the subsequent application uses this data as the standard for 500mA current detection. After the test is finished, let the load switching circuit enter a high-impedance state, which will not affect the switching power supply control circuit.

A person skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the system, the device and the unit described above can refer to the corresponding process in the foregoing method embodiment, and details are not described herein again.

In the several embodiments provided by the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed. Another point, the mutual coupling or straightness shown or discussed The coupling or communication connection may be an indirect coupling or communication connection through some interface, device or unit, and may be in electrical, mechanical or other form.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a standalone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, or all or part of the technical solution, may be embodied in the form of a software product stored in a storage medium. A number of instructions are included to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: a U disk, a mobile hard disk, a read only memory (English full name: Read-Only Memory, English abbreviation: ROM), a random access memory (English full name: Random Access Memory, English abbreviation: RAM), magnetic A variety of media that can store program code, such as a disc or a disc.

The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that The technical solutions described in the embodiments are modified, or the equivalents of the technical features are replaced by the equivalents of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A switching power supply circuit, comprising: a switching power supply control circuit, a load switching circuit and a load current detecting circuit; the load switching circuit includes a target load; and the switching power supply control circuit includes a power load;

   The switching power supply control circuit is connected to the load switching circuit; the load current detecting circuit is connected to the load switching circuit;

   The load switching circuit is configured to integrate the target load into the power load;

   The load current detecting circuit is configured to detect a voltage value corresponding to the target load;

   The switching power supply control circuit is configured to detect a first detection current value and a second detection current value, where the first detection current value is the switching power supply when the power load is in a sleep state and the target load is in a high resistance state a current value corresponding to the circuit, wherein the second detection current value is a current value corresponding to the switching power supply circuit when the power load is in a sleep state and a current value corresponding to the target load is equal to a target current value;

   The switching power supply control circuit is further configured to calculate a current value corresponding to the target load according to a voltage value corresponding to the target load, and adjust a current value corresponding to the target load to the target current value;

   The switching power supply control circuit is further configured to determine a detection value corresponding to the difference between the second detection current value and the first detection current value as the target current value.
2. The switching power supply circuit according to claim 1, wherein the load switching circuit further comprises a digital-to-analog converter DAC, an NMOS transistor, and a serial peripheral interface SPI;

   The switching power supply control circuit and the load current detecting circuit are connected to the load switching circuit through the SPI;

   One end of the DAC is connected to the SPI, the other end of the DAC is connected to the gate of the NMOS transistor, the drain of the NMOS transistor is connected to the target load, and the source of the NMOS transistor is grounded;

   The switching power supply control circuit is further configured to control an output voltage of the DAC, the output voltage is used to control a gate voltage of the NMOS transistor, and the gate voltage is used to adjust a conduction of the NMOS transistor Impedance, the on-resistance is used to adjust a current value of the target load.
3. The switching power supply circuit according to claim 2, wherein said load switching power The circuit further includes a sustain level resistor for maintaining a fixed level to the NMOS transistor, one end of the sustain level resistor being connected to a gate of the NMOS transistor, the sustain level resistor The other end of the ground.
4. The switching power supply circuit according to claim 1, wherein the load current detecting circuit comprises: a differential amplifying circuit, a first inverse proportional amplifying circuit, a gain adjusting circuit, a voltage following circuit, and a second inverse proportional amplifying circuit. And an analog to digital converter ADC;

   An input end of the differential amplifying circuit is connected to a target load, and an output end of the differential amplifying circuit is connected to the first inverse proportional amplifying circuit and the gain adjusting circuit;

   The voltage follower circuit is connected to the first inverse proportional amplification circuit and the second inverse proportional amplification circuit;

   The amplification ratio corresponding to the differential amplification circuit is 1:1; the amplification ratio corresponding to the second direction proportional amplification circuit is 1:1;

   The first inverse proportional amplification circuit is configured to amplify a first output voltage of the differential amplification circuit, and an amplification ratio corresponding to the first reverse proportional amplification circuit is a target value;

   The voltage follower circuit is configured to buffer the first output voltage;

   The gain adjustment circuit is configured to adjust the target value;

   The ADC is configured to sample an output terminal voltage of the second inverse proportional amplification circuit and an output terminal voltage of the gain adjustment circuit, and an output terminal voltage of the second inverse proportional amplification circuit is used to determine a target load corresponding to the target a voltage value, the output voltage of the gain adjustment circuit being an adjustment factor of the target value.
5. The switching power supply circuit according to claim 4, wherein said differential amplifier circuit comprises a first operational amplifier A _1; the ratio of the first reverse amplifier circuit includes a second operational amplifier A _2, the first resistors R ₁ a second resistor R ₂ , a third resistor R ₃ , a fourth resistor R ₄ , a fifth resistor R _{5 ,} and a PMOS transistor T ₂ ; the gain adjustment circuit includes a third operational amplifier A ₃ , the R ₅ and the T ₂ ; the voltage follower circuit includes a fourth operational amplifier A ₄ ; the second inverse proportional amplification circuit includes a fifth operational amplifier A ₅ , a sixth resistor R ₆ , a seventh resistor R ₇ and an eighth resistor R ₈ ;

   One end of the positive input terminal of the A ₁ is connected to the target load, the inverting input of A ₁ is connected to the other end of the target load, the terminating end of the output A ₁ of said R _2, said R ₂ inverting input terminal of the other end of the a ₂ and R ₃ of one end, the other end of R ₃ end of the R _4, the R output of said another end of a _{2 4} end, the forward end of the input a ₂ of the R ₁ end, the other end of the end of R _1;

   The inverting input terminal of the A ₃ is connected to the reference voltage, the forward input terminal of the A ₃ is connected to the output end of the A ₁ , and the output terminal of the A ₃ is connected to the gate of the T ₂ , the T ₂ connected to the drain of R ₃ and the other end of end of the intermediate node between R _4, the T electrode connected to the source ₂ end R _5, said R _5;

   ₄ A the positive input terminal of the output A ₂ of the termination, the termination ₄ A reverse input terminal of the output A _4;

   The reverse input terminal of the A ₅ is connected to one end of the R ₇ and one end of the R ₈ , the other end of the R ₇ is connected to the output end of the A ₄ , and the other end of the R ₈ is connected to the a ₅ is an output terminal, the input terminal a ₅ forward end of said R _6, said R ₆ is other end connected to ground;

   One end of the ADC is connected to the output end of the A _{5 and} the output end of the A ₃ , and the other end of the ADC is connected to the load switching circuit.
6. The switching power supply circuit according to claim 5, wherein said R ₁ to said R ₈ correspond to an accuracy of one percent.
7. The switching power supply circuit according to any one of claims 1 to 6, wherein the target load corresponds to an accuracy of one percent.
8. The switching power supply circuit according to any one of claims 1 to 6, wherein the target load has a resistance of 0.5 ohm.
9. A method for detecting a power source current, comprising:

   The switching power supply circuit determines a target current value;

   The switching power supply circuit sets the target load to a high impedance state, sets the power load to a sleep state, and records a first detected current value corresponding to the switching power supply circuit;

   The switching power supply circuit sets a target load to an operating state, and detects a voltage value corresponding to the target load;

   The switching power supply circuit calculates a current value corresponding to the target load according to the voltage value;

   When it is determined that the current value corresponding to the target load is not equal to the target current value, the switching power supply circuit adjusts a current value corresponding to the target load to the target current value;

   When it is determined that the current value corresponding to the target load is equal to the target current value, the switching power supply circuit records a second detected current value corresponding to the switching power supply circuit;

   The switching power supply circuit determines a difference between the second detected current value and the first detected current value as a detected value corresponding to the target current value.
10. The method according to claim 9, wherein the switching power supply circuit determines that the difference between the second detected current value and the first detected current value is a detected value corresponding to the target current value, and then includes:

    The switching power supply circuit sets the target load to a high impedance state, and sets the power load to an active state.

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