JP4821339B2 - Bidirectional pulse signal transmission circuit and isolated switching power supply - Google Patents

Description

  The present invention relates to a bidirectional pulse signal transmission circuit that bidirectionally transmits a pulse signal between a primary and a secondary using a single pulse transformer, and an insulated switching power supply device including the bidirectional pulse signal transmission circuit.

  A conventional synchronous rectification type forward converter is disclosed in Patent Document 1. FIG. 1 shows a circuit of a synchronous rectification type forward converter disclosed in Patent Document 1.

  In the circuit shown in FIG. 1, when the primary switch element 102 on the primary side of the transformer 104 is turned on, the secondary rectifier side synchronous rectifier element 105 is turned on by the voltage generated in the secondary winding 104b of the transformer 104, and vice versa. At the same time, the commutation side synchronous rectifier 106 is turned off. Here, if the timing at which the commutation-side synchronous rectifying element 106 is turned off is delayed, a short-circuit path passing through the two switch elements 105 and 106 is formed. Therefore, the switch element 107 is connected in series with the tertiary winding 104c of the transformer 104. The switch element 107 is turned on by a control signal via the pulse transformer 111 at the timing when the primary side main switch element 102 is turned on.

With this configuration, the charge of the parasitic capacitance of the commutation side synchronous rectification element 106 is extracted through the switch element 107 immediately before the primary side main switch element 102 is turned on, and the commutation side synchronous rectification element 106 is quickly turned off. Therefore, a short circuit is prevented.
Japanese Patent No. 3339452

  Usually, in a signal transmission circuit using one pulse transformer (an insulating transformer in which one core is provided with one or more windings for a primary side and a secondary side in one core), the above-mentioned Patent Document 1 discloses. As shown, one-way signal transmission is performed. When signal transmission is required not only from the primary side circuit to the secondary side circuit but also from the secondary side circuit to the primary side circuit, an individual pulse transformer is used for each. Become.

  However, as the number of pulse transformers increases, the area of the circuit board increases as a matter of course, the cost increases accordingly, and the entire apparatus increases in size. In particular, when a high voltage pulse transformer satisfying the primary-secondary breakdown voltage defined by the safety standard is required, the insulation structure needs to be devised, and the shape is large and expensive.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a bidirectional pulse signal transmission circuit that performs bidirectional signal transmission using a single pulse transformer, and an insulated switching power supply device including the bidirectional pulse signal transmission circuit.

In order to solve the above problems, the bidirectional pulse signal transmission circuit of the present invention is configured as follows.
A primary side pulse signal transmitter (71) and a primary side pulse signal receiver (72) are provided on the primary side of the pulse transformer, and a secondary side pulse signal transmitter (81) is provided on the secondary side of the pulse transformer. And a secondary side pulse signal receiver (82),
The primary side pulse signal transmission unit (71) is composed of a circuit for inputting a primary side pulse signal to the primary side coil of the pulse transformer,
The primary side pulse signal receiving unit (72) is generated in the primary side coil of the pulse transformer in a state where the primary side pulse signal from the primary side pulse signal transmitting unit (71) is not inputted . A circuit for inputting a signal having a polarity opposite to that of the primary side pulse signal from the primary side pulse signal transmission unit ;
The secondary side pulse signal transmitter (81) comprises a circuit for inputting a secondary side pulse signal to a secondary side coil of the pulse transformer,
The secondary pulse signal receiver (82) is generated in the secondary coil of the pulse transformer in a state where the secondary pulse signal from the secondary pulse signal transmitter (81) is not input . The secondary side pulse signal from the secondary side pulse signal transmission unit is composed of a circuit for inputting a signal having a polarity opposite to that of the secondary side pulse signal ,
The primary-side pulse signal and the secondary-side pulse signal are generated at timings that are different from each other in a predetermined cycle.
In this way, a pulse signal can be transmitted bidirectionally between the primary and secondary using a single pulse transformer.

  At least one of the primary side coil and the secondary side coil of the pulse transformer may be a single winding, that is, the primary side pulse signal transmitting unit and the primary side pulse signal receiving unit are connected to the primary side coil. Both may be connected, or both the secondary pulse signal transmitter and the secondary pulse signal receiver may be connected to the secondary coil.

  The primary side pulse signal and the secondary side pulse signal have information at timing (phase) in a predetermined cycle, for example.

The insulated switching power supply device of the present invention is configured as follows.
A power transmission transformer having at least a primary side coil and a secondary side coil, and a main switch element that switches a direct current input or a direct current input including an alternating current component to the primary side coil of the power transmission transformer to convert it into an alternating current. The secondary circuit which has a primary circuit, the rectification smoothing circuit which rectifies and smooths the output from the secondary side coil of the said electric power transmission transformer, The bidirectional | two-way pulse signal transmission circuit in any one of Claims 1-3 , With
The bidirectional pulse signal transmission circuit transmits a control signal (timing signal) generated in the primary circuit to the secondary circuit, and transmits a control signal generated in the secondary circuit to the primary circuit.

According to the present invention, the following effects can be obtained.
Since one pulse transformer is used both for transmission of the primary side pulse signal from the primary side to the secondary side and transmission of the secondary side pulse signal from the secondary side to the primary side, Bidirectional pulse signal transmission that requires a pulse transformer can be realized with a single pulse transformer. As a result, it is possible to reduce the size and cost of the bidirectional pulse signal transmission circuit and the insulated switching power supply device including the bidirectional pulse signal transmission circuit.

<< First Embodiment >>
A bidirectional pulse signal transmission circuit according to the first embodiment will be described with reference to FIGS.
FIG. 2 is a circuit diagram of the bidirectional pulse signal transmission circuit according to the first embodiment, and FIG. 3 is a waveform diagram at each point.

  This bidirectional pulse signal transmission circuit includes a pulse transformer 48 having a primary winding (primary coil) 48A and a secondary winding (secondary coil) 48B. On the primary side of the pulse transformer 48, a primary side power supply terminal 37, a primary side pulse signal input terminal 38, a primary side ground 39, and a primary side pulse signal output terminal 40 are provided. On the secondary side of the pulse transformer 48, a secondary side power supply terminal 50, a secondary side pulse signal input terminal 51, a secondary side ground 52, and a secondary side pulse signal output terminal 49 are provided.

  As shown in FIG. 2, a series circuit of an NPN transistor 45 and a PNP transistor 46 is connected between the primary side power input terminal 37 and the primary side ground 39. The bases of the NPN transistor 45 and the PNP transistor 46 are connected in common, and a parallel circuit of a capacitor 41 and a resistor 42 is connected between the connection point and the primary side pulse signal input terminal 38. A diode 63 having a forward direction from the collector to the emitter is connected between the emitter and collector of the PNP transistor 46.

  A primary winding 48A of the pulse transformer 48 is connected between the connection point of the two transistors 45 and 46 and the primary pulse signal output terminal 40. An N-channel MOSFET 47 is connected between the primary side pulse signal output terminal 40 and the primary side ground 39. A capacitor 43 is connected between the gate of the FET 47 and the primary side pulse signal input terminal 38, and a resistor 44 is connected between the gate of the FET 47 and the primary side ground 39.

  In this example, the primary side circuit and the secondary side circuit of the pulse transformer 48 are symmetrical. That is, a series circuit of an NPN transistor 54 and a PNP transistor 55 is connected between the secondary power supply terminal 50 and the secondary ground 52. The bases of the NPN transistor 54 and the PNP transistor 55 are connected in common, and a parallel circuit of a capacitor 56 and a resistor 57 is connected between the connection point and the secondary pulse signal input terminal 51. A diode 64 having a forward direction from the collector to the emitter is connected between the emitter and collector of the PNP transistor 55. A secondary winding 48B of the pulse transformer 48 is connected between the connection point of the two transistors 54 and 55 and the secondary pulse signal output terminal 49. An N-channel MOSFET 53 is connected between the secondary side pulse signal output terminal 49 and the secondary side ground 52. A capacitor 58 is connected between the gate of the FET 53 and the secondary side pulse signal input terminal 51, and a resistor 59 is connected between the gate of the FET 53 and the secondary side ground 52.

  First, predetermined loads are respectively connected between the primary side pulse signal output terminal 40 and the primary side ground 39 and between the secondary side pulse signal output terminal 49 and the secondary side ground 52. Shall.

  In a state where no pulse signal is input from either the primary side pulse signal input terminal 38 or the secondary side pulse signal input terminal 51, the NPN transistors 45 and 54 are both in the off state because the base potential is low. Further, when the primary pulse signal input terminal 38 is viewed from the primary pulse signal output terminal 40, the emitter-base of the PNP transistor 46 is in the forward direction. Similarly, when the secondary pulse signal input terminal 51 is viewed from the secondary pulse signal output terminal 49, the emitter-base of the PNP transistor 55 is in the forward direction. Therefore, the potentials of the primary side pulse signal output terminal 40 and the secondary side pulse signal output terminal 49 are both at the ground level. The FETs 47 and 53 are both off because their gate potential is at the ground level.

  Here, when a pulse signal is input from the primary side pulse signal input terminal 38, the transistor 45 is turned on only while the signal is at the H level (high level). When a pulse signal is applied through the capacitor 43 and the resistor 44, the FET 47 is also temporarily turned on. Although the emitter potential increases, the transistor 46 remains off because the base potential also increases. Therefore, a current flows from the primary power supply terminal 37 through the transistor 45, the primary winding (primary coil) 48A, and the FET 47.

  Even when this current flows, the potential of the primary side pulse signal output terminal 40 remains at the ground level. That is, no pulse signal is received.

  The voltage across the primary winding 48A (voltage based on the primary pulse signal output terminal 40) is at the H level only while the current flows through the primary winding 48A.

  On the other hand, the secondary winding (secondary side coil) 48B reaches the secondary side pulse signal output terminal 49 from the ground through the diode 64 connected in parallel to the transistor 55 by the current flowing through the primary winding 48A. Current flows. At this time, the transistor 54 and the FET 53 remain off. As a result, a pulse voltage is generated at the secondary side pulse signal output terminal 49.

  Note that the voltage across the secondary winding 48B (the voltage based on the secondary pulse signal output terminal 49) has a ground level at the opposite side (emitter of the transistor 55), so that the current flows. Only negative voltage.

  Since this bidirectional pulse signal transmission circuit is symmetrical between the primary and secondary sides, the same operation as described above is performed when transmitting a pulse signal from the secondary side to the primary side. Therefore, while the pulse signal is input from the secondary side pulse signal input terminal 51, the voltage across the primary winding 48A (the voltage based on the primary side pulse signal output terminal 40) is the opposite side (transistor 46 emitter) is at the ground level, so it becomes a negative voltage only while the current is flowing.

  Further, the voltage across the secondary winding 48B (voltage based on the secondary pulse signal output terminal 49) is at the H level only while the current flows through the secondary winding 48B.

  In this way, the voltage across the primary winding 48A and the secondary winding 48B becomes a pulse with reverse polarity (reverse waveform change) when the transmission direction of the pulse signal is reversed.

Next, the circuit operation will be described according to the voltage waveform of each part in FIG.
When the primary pulse signal is input from the primary side pulse signal input terminal 38 at the timing t1, the pulse signal transmitted from the primary circuit is output to the secondary side pulse signal output terminal 49 as described above. .

  When the pulse signal is input from the secondary side pulse signal input terminal 51 at the timing t2, the pulse signal transmitted from the secondary circuit is output to the primary side pulse signal output terminal 40 as described above.

  By the above-described operation, the pulse signal transmitted from the primary side pulse signal transmission unit of the primary side circuit is output to the secondary side pulse signal output terminal of the secondary side circuit, and the secondary side pulse signal of the secondary side circuit is output. Since the pulse signal transmitted from the transmission unit is output to the primary side pulse signal output terminal of the primary side circuit, bidirectional transmission between the primary and secondary can be performed by one pulse transformer 48.

  However, even if a pulse signal is transmitted from the primary circuit to the secondary circuit, if the N-channel MOSFET 53 is turned on, the PNP transistor 55 → the secondary winding 48B of the pulse transformer → the N-channel MOSFET 53 is short-circuited. A pulse signal cannot be output from the secondary side pulse signal output terminal 49. Similarly, even if a pulse signal is transmitted from the secondary circuit to the primary circuit, if the N-channel MOSFET 47 is on, a short circuit occurs in the loop of the PNP transistor 46 → the pulse transformer primary winding 48A → the N-channel MOSFET 47. A pulse signal cannot be output from the primary side pulse signal output terminal 40. In other words, if the generation timing of the pulse signal transmitted from the primary circuit to the secondary circuit and the pulse signal transmitted from the secondary circuit to the primary circuit overlap, transmission is impossible, so transmission is performed with the phases shifted from each other. To do.

  As shown in FIG. 3, the signal transmitted from the primary circuit to the secondary circuit and the signal transmitted from the secondary circuit to the primary circuit have opposite polarities with respect to the pulse transformer 48. During a period in which no pulse signal is input from the primary pulse signal input terminal 38, the primary winding 48A of the pulse transformer is in the direction from the source to the drain of the N-channel MOSFET 47, the parasitic diode of the N-channel MOSFET 47 → the primary winding of the pulse transformer. There is a flow path of line 48A → PNP transistor 46, which is short-circuited. Similarly, during a period in which no pulse signal is input from the secondary pulse signal input terminal 51, the pulse transformer secondary winding 48B has a parasitic diode → pulse of the N-channel MOSFET 53 in the direction from the source to the drain of the N-channel MOSFET 53. There is a flow path of the transformer secondary winding 48B → PNP transistor 55, which is short-circuited. In this way, during the period when the pulse signal is not generated, both ends of the coil of the pulse transformer 48 on the pulse signal transmission unit side are short-circuited, so that it is not easily affected by external noise.

  In the bidirectional pulse signal transmission circuit shown in the first embodiment, the transmission timings of the pulse signal transmitted from the primary circuit to the secondary circuit and the pulse signal transmitted from the secondary circuit to the primary circuit with respect to a predetermined cycle It can be used as a timing signal for designating a specific timing.

  Further, if the voltage of the primary power supply terminal 37 and the secondary power supply terminal 50 is configured to be adjustable, a pulse signal transmitted from the primary side to the secondary side and a pulse signal transmitted from the secondary side to the primary side. Therefore, it is possible to exchange information between primary and secondary by amplitude modulation.

<< Second Embodiment >>
Next, an insulated switch power supply device according to a second embodiment will be described with reference to FIGS.
FIG. 4 is a circuit diagram of an insulated switch power supply device according to the second embodiment, and FIG. 5 is a waveform diagram at each point.

  In the second embodiment, the control circuit of the forward converter includes the bidirectional pulse signal transmission circuit shown in the first embodiment, and the on-timing of the main switch is transmitted from the primary circuit to the secondary circuit. Is transmitted from the secondary circuit to the primary circuit.

  The power transmission transformer 4 includes a primary winding 4A, a secondary winding 4B, and a tertiary winding 4C. A main switch element 5 is connected in series to the primary winding 4A, and a capacitor 3 is connected between the input terminals 1 and 2. A choke coil 9 and a rectifying switch element 6 are connected in series to the secondary winding 4 </ b> B of the power transmission transformer 4, and a smoothing capacitor 12 is connected between the output terminals 10 and 11. Further, the choke coil 9 and the smoothing capacitor 12 constitute a loop, and the commutation switch element 7 is provided at a position serving as a commutation path when the excitation energy of the choke coil 9 is released.

  As shown in FIG. 4, a series circuit of a primary winding 4 </ b> A of a power transmission transformer 4 and a main switch element 5 is connected between a + input 1 and a −input (ground) 2 of a DC input power supply. A capacitor 3 is connected between the two inputs 1-2.

  The gate of the main switch element 5 is composed of AND gate 20, inverters 14 and 15, NOR gate 60, MOSFETs 47 and 21, capacitors 19, 43 and 62, resistors 16, 18, 23, 61 and 44, and diodes 17 and 22. The control circuit on the next side is connected.

  The inverters 14 and 15, the capacitor 19, the resistors 16 and 18, and the diode 17 constitute an oscillation circuit (multivibrator) 13.

  A primary side pulse signal is generated by an integration circuit including a resistor 61 and a capacitor 62 and a NOR gate 60. Further, the primary side pulse signal is applied to the gate of the FET 47 through the capacitor 43 and the resistor 44 to constitute a current path of the primary winding 48A of the pulse transformer 48. Even if such a rectangular wave pulse signal is transmitted to the secondary side, the MOSFET 65 can be turned on.

  Between the output terminals 10-11, a secondary-side control circuit including a comparator 30, an AND gate 29, a reference voltage source 36, capacitors 32, 33, 58, resistors 31, 34, 35, 59, and an FET 53 is provided. Yes.

  When a DC voltage is input between the + input 1 and the input 2 of the DC input power supply, the main switch element 5 performs a switching operation so that the DC is converted into AC, and the secondary winding from the primary winding 4A of the power transmission transformer 4 AC power is transmitted to the winding 4B. (1) in FIG. 5 is the drain voltage of the main switch element 5, (2) is the drain current, and (3) is the waveform of the gate voltage. In the secondary rectifier circuit, the rectifier switch element 6 and the commutation switch element 7 are driven at complementary timings to rectify the alternating current, and are smoothed by the primary winding 9A of the choke coil 9 and the smoothing capacitor 12 to become DC power again. It is converted and output from + output 10 and -output 11.

Detailed operation is as follows.
In the control circuit on the primary side, the oscillation circuit 13 oscillates with the maximum duty ratio (see (4) and (5) in FIG. 5).

  At the timing t1 shown in FIG. 5, the output voltage of the inverter 14 (see (5) in FIG. 5) is inverted from the H level to the L level, and the first input of the NOR gate 60 becomes L, but the second input also Since it is at the L level, the output voltage of the NOR gate 60 is inverted from the L level to the H level (see (6) and (7) in FIG. 5).

  When the output voltage of the NOR gate 60 becomes H level, the gate of the N-channel MOSFET 47 is charged through the capacitor 43 and is turned on, and the current flows through the NOR gate 60 output → the primary winding 48A of the pulse transformer → the FET 47 → the input 2 Flows. As a result, the gate of the N-channel MOSFET 65 is charged by the pulse signal voltage appearing at the tertiary winding 48C of the pulse transformer 48.

  When the FET 65 is turned on, the electric charge accumulated in the gate of the commutation switch element 7 during the off period of the main switch element 5 is discharged and turned off. By inverting the output voltage of the inverter 14 from the H level to the L level, the output voltage of the inverter 15, that is, the first input of the AND gate 20 (see (4) in FIG. 5) is inverted from the L level to the H level. Since the drain voltage of the N-channel MOSFET 21 which is the second input of the AND gate 20 is charged through the diode 22 and the resistor 23 during the period when the output voltage of the inverter 14 is at the H level, the drain voltage is at the H level. Is inverted from the L level to the H level, and the main switch element 5 is turned on.

  While the H → L inversion of the inverter 14 is propagated through the path of the inverter 15 → the AND gate 20 → the main switch element 5, the pulse signal is also propagated through the path of the NOR gate 60 → the pulse transformer 48 → the FET 65 → the commutation switch element 7. Since the commutation switch element 7 is turned off, the commutation switch element 7 is turned off immediately before the main switch element 5 is turned on, and no short-circuit current in the loop caused by the rectifying switch element 6 and the commutation switch element 7 is generated. High efficiency operation becomes possible.

  After the L → H inversion of the inverter 15, the second input of the NOR gate 60 is inverted from the L level to the H level through the time constant circuit of the resistor 61 and the capacitor 62 (see (6) in FIG. 5). Is inverted from H level to L level, and the pulse signal disappears.

  On the other hand, on the secondary side, when the output of the comparator 30 is inverted, the output of the AND gate 29 is inverted from L to H. The output of the AND gate 29 itself is a step-like signal (thereby, the FET 53 returns to a low level when the FET 53 is turned off, so that the waveform looks like a pulse). By applying this signal to the FET 53 via the capacitor 58 and the resistor 59, a current path of the secondary winding 48B is temporarily formed. Therefore, a pulse-like signal is transmitted from the secondary side to the primary side. The signal transmitted to the primary side is applied to the gate of the FET 21, and the FET 21 is turned on, so that the output of the AND gate 20 becomes low level and the FET 5 is turned off.

  In the secondary side control circuit, the comparator 30 compares the output voltage with the divided voltage of the reference voltage source 36. A ramp voltage obtained by integrating the voltage across the primary winding 9A of the choke coil 9A (see (8) in FIG. 5) by the resistor 31 and the capacitor 32 is superimposed on the inverting input (−) of the comparator 30 via the capacitor 33. Thus, the ON period of the main switch element 5 gradually decreases. Since the output voltage input to the non-inverting input (+) of the comparator 30 includes a ripple component, it gradually increases during the ON period of the main switch element 5 (see (9) in FIG. 5).

  When the non-inverting input (+) of the comparator 30 exceeds the inverting input (−) at the timing t2 of the ON period of the main switch element 5, the output voltage of the comparator 30 is inverted from the L level to the H level ((( 10)). Since the voltage of the secondary winding 9B of the choke coil 9 (see (11) in FIG. 5) input to the other side of the AND gate 29 is at the H level during the ON period of the main switch element 5, the output voltage L of the comparator 30 Since the AND gate 29 is turned on along with the H inversion (see (12) in FIG. 5), the gate of the FET 53 is also turned on through the capacitor 58, so the AND gate 29 → the secondary winding 48B of the pulse transformer → the FET 53 → Current flows through the path of the converter −output 11 and a pulse signal is generated in the primary winding 48 </ b> A of the pulse transformer 48.

Depending on the winding direction of each winding of the pulse transformer 48, the pulse signal generated at t2 has the opposite polarity to the pulse signal generated at t1. (See (13) in Fig. 5)
The pulse signal generated at t2 is transmitted from the secondary circuit to the primary circuit, and current flows through the path of the NOR gate 60 → the primary winding 48A of the pulse transformer → the gate of the N-channel MOSFET 21, and the FET 21 is turned on. When the FET 21 is turned on, the charge accumulated in the output capacitance is discharged and the drain voltage is changed from H level to L level, so that the output voltage of the AND gate 20 is inverted from H level to L level ((3 in FIG. 5). )reference). That is, the ON period of the main switch element 5 is defined as a period from the start of the ON period until the non-inverting input (+) of the comparator 30 exceeds the inverting input (−), and the ON period becomes longer as the output voltage decreases. When the output voltage increases, the on-period is shortened. For this reason, pulse width control is performed according to the output voltage, and the output voltage is stabilized.

  In the second embodiment, instead of using a conventional error amplifier and photocoupler, control is performed using a comparator and a pulse transformer, and there is a feature that a high-speed response can be made to fluctuations in input voltage and output current. . Furthermore, since a photocoupler having an absolute maximum rated temperature of about 100 ° C. and a problem of CTR aging deterioration is unnecessary, a switching power supply device with a wide operating ambient temperature and high reliability can be configured.

  The present invention is not limited to the first and second embodiments, and various applications are possible. The use of the primary-secondary bidirectional pulse signal transmission circuit is not limited to the transmission of the on / off timing of the main switch element shown in the second embodiment, and an amplitude-modulated error signal is transmitted from the secondary circuit. The main switch element may be configured to be PWM-controlled based on the error signal transmitted to the primary circuit and demodulated.

  Further, a signal related to the protection operation such as output overvoltage protection, output undervoltage protection, overheat protection, etc. may be transmitted between the primary and secondary.

  Further, instead of transmitting the first and second pulse signals once every switching period, a plurality of pulse signals may be transmitted.

  Further, the first pulse signal transmitted from the primary circuit to the secondary circuit and the second pulse signal transmitted from the secondary circuit to the primary circuit may be configured to have the same polarity with respect to the transformer. Good.

  In the first embodiment, an example using a pulse transformer 48 having one primary winding 48A as a primary side coil and one secondary winding 48B as a secondary side coil is shown. In the second embodiment, Although the example using the pulse transformer 48 having one primary winding 48A as the primary side coil and two secondary windings 48B and 48C as the secondary side coil has been shown, the present invention is limited to these. It is not a thing. For example, a pulse transformer having a plurality of primary coils and a plurality of secondary coils may be used, and a pulse signal transmitter / receiver corresponding to the number of coils may be provided.

It is a circuit diagram which shows the structure of the insulation type switching power supply device which concerns on patent document 1. 1 is a circuit diagram showing a configuration of a bidirectional pulse signal transmission circuit according to a first embodiment. FIG. It is a wave form diagram of the principal part of the same bidirectional pulse signal transmission circuit. It is a circuit diagram of the insulation type switching power supply device concerning a 2nd embodiment. It is a wave form diagram of the principal part of the insulation type switching power supply device.

Explanation of symbols

1-+ input terminal of isolated type switching power supply unit 2 --input terminal of isolated type switching power supply unit 4-power transmission transformer 4A-primary winding (primary coil)
4B-2 secondary winding (secondary coil)
4C-tertiary winding 5-main switch element 6-rectifier switch element 7-commutation switch element 9-choke coil 10-+ output terminal of isolated switching power supply 11-output terminal of isolated switching power supply 13- Oscillator 36-Reference voltage source 37-Primary side power supply terminal 38-Primary side pulse signal input end 39-Primary side ground 40-Primary side pulse signal output end 48-Pulse transformer 48 A Primary winding (1 Secondary coil)
48B-2 secondary winding (secondary coil)
48C-tertiary winding (secondary coil)
49-2 Secondary side pulse signal output terminal 50-2 Secondary side power supply terminal 51-2 Secondary side pulse signal input terminal 52-2 Secondary side ground 71-1 Primary side pulse signal transmitter 72-1 Primary side pulse signal receiver 81 -Secondary side pulse signal transmission unit 82-2 Secondary side pulse signal reception unit

Claims (4)

A primary side pulse signal transmitter and a primary side pulse signal receiver are provided on the primary side of the pulse transformer, and a secondary side pulse signal transmitter and a secondary side pulse signal receiver are provided on the secondary side of the pulse transformer. With
The primary side pulse signal transmission unit includes a circuit for inputting a primary side pulse signal to a primary side coil of the pulse transformer,
Wherein the primary side pulse signal receiving unit generated in the pulse transformer primary coil and the primary-side pulse signal in a state of not being inputted from said primary side pulse signal transmitter, the primary side pulse signal It consists of a circuit that inputs a signal having a polarity opposite to that of the primary side pulse signal from the transmitter ,
The secondary side pulse signal transmission unit is composed of a circuit for inputting a secondary side pulse signal to the secondary side coil of the pulse transformer,
The secondary pulse signal receiving unit is generated at the secondary coil of the pulse transformer in a state where the secondary pulse signal from the secondary side pulse signal transmitter is not input, the secondary pulse signal It consists of a circuit that inputs a signal having a polarity opposite to that of the secondary pulse signal from the transmitter ,
The primary-side pulse signal and the secondary-side pulse signal are generated at timings that are different from each other in a predetermined cycle,
A bidirectional pulse signal transmission circuit, wherein a pulse signal is bidirectionally transmitted between primary and secondary using a single pulse transformer.   The bidirectional pulse signal transmission circuit according to claim 1, wherein at least one of the primary side coil and the secondary side coil of the pulse transformer is a single winding.   The bidirectional pulse signal transmission circuit according to claim 1, wherein the primary side pulse signal and the secondary side pulse signal have information at a timing in a predetermined cycle. A power transmission transformer having at least a primary side coil and a secondary side coil, and a main switch element that switches a direct current input or a direct current input including an alternating current component to the primary side coil of the power transmission transformer to convert it into an alternating current. a primary circuit, a secondary circuit having a rectifying smoothing circuit for rectifying and smoothing the output from the secondary coil of the power transmission transformer, bidirectional pulse signal transmission according to any one of claims 1 to 3 With circuit,
The bidirectional pulse signal transmission circuit transmits a control signal generated in the primary circuit to the secondary circuit, and transmits a control signal generated in the secondary circuit to the primary circuit. Insulated switching power supply.

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