Bidirectional power supply synchronous rectification logic drive circuit and bidirectional power supply

Abstract

The utility model discloses a logic drive circuit for synchronous rectification of a bidirectional power supply and the bidirectional power supply. The circuit comprises a synchronous rectification chip, a control circuit and a control signal port. The circuit is connected to a control circuit through a control signal port, so that the power supply of the synchronous rectification chip is adjusted, and the working state of the synchronous rectification chip is controlled. The circuit is simple in principle and process, control driving of the synchronous rectification chip of the bidirectional power supply is realized by using fewer devices and a simpler control thought, and the effect of preventing false triggering of the synchronous rectification chip during reverse power supply of the bidirectional power supply is achieved; the purpose of preventing main power driving disorder during reverse power supply of the bidirectional power supply with synchronous rectification is achieved, and the circuit can be widely applied to development of battery bidirectional charging and discharging switching power supply circuit products.

Description

Technical Field

[0001] The utility model belongs to the field of switching power supplies, and in particular relates to a logic drive circuit for synchronous rectification of a bidirectional power supply and a bidirectional power supply. Background Art

[0002] In battery systems, bidirectional power supplies are often used to achieve bidirectional energy transfer, battery protection, and improve energy conversion efficiency. In bidirectional charging and discharging switching power supplies, they generally have the characteristics of large output current. When using traditional diodes for secondary side rectification, they often cause large losses due to the voltage drop of the diode, resulting in low circuit efficiency. Therefore, most circuits will use synchronous rectification schemes to improve circuit efficiency. However, in reverse charging conditions, it is very easy to cause confusion in the main power drive due to the false triggering of the synchronous rectification chip. The reason is that the synchronous rectification chip turns on the synchronous rectification tube by detecting that the gate leakage voltage of the secondary side synchronous rectification switch tube is lower than a certain negative value, and turns off the synchronous rectification tube by detecting that the gate leakage current of the secondary side synchronous rectification switch tube is 0. Under reverse power supply conditions, the switching action of the power tube on the secondary side will generate the above two signals, thereby falsely triggering the opening and closing of the synchronous rectification tube. Since the synchronous rectification tube is connected in parallel with the main power tube, the main power drive signal and the falsely triggered synchronous rectification signal are equivalent to "or operation logic", thereby disrupting the main power drive logic, causing reverse charging to fail to work normally.

[0003] The utility model designs a bidirectional power supply synchronous rectification logic driving circuit, which can control the power supply of a synchronous rectification chip and eliminate the interference of the synchronous rectification chip, so as to achieve the effect of normal working of reverse charging. Utility Model Content

[0004] The utility model aims to overcome at least one defect (shortcoming) in the above-mentioned prior art and provide a logic drive circuit and a bidirectional power supply with synchronous rectification to solve the problem of driving confusion of the main power of the bidirectional power supply with synchronous rectification when reverse power is supplied.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] In the first aspect, a logic driving circuit for bidirectional power synchronous rectification is provided, including a synchronous rectification chip, a control circuit and a control signal port, wherein the control circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first transistor Q1, a second transistor Q2, a first optical coupler OC1, a power input port Vin, an output power interface Vo, and an output ground port -Vo;

[0007] The emitter of the first transistor Q1 is connected to the VDD power supply end of the synchronous rectification chip, the collector of the first transistor Q1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to the output power interface Vo, the base of the first transistor Q1 is connected to one end of the second resistor R2, one end of the third resistor R3 and the collector of the second transistor Q2, the other end of the second resistor R2 is connected to the output power interface Vo, the emitter of the second transistor Q2 is connected to the output ground port -Vo, the base of the second transistor Q2 is connected to the other end of the third resistor R3, one end of the fourth resistor R4 and one end of the fifth resistor R5, the other end of the fourth resistor R4 is connected to the emitter of the secondary transistor of the first optical coupler OC1, the other end of the fifth resistor R5 is connected to the output ground port -Vo, the collector of the secondary transistor of the first optical coupler OC1 is connected to the output power interface Vo, the anode of the primary light emitting diode of the first optical coupler OC1 is connected to the power input port Vin, the cathode of the primary light emitting diode of the first optical coupler OC1 is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is connected to the control signal port.

[0008] In the second aspect, a logic drive circuit for bidirectional power supply synchronous rectification is provided, comprising a synchronous rectification chip, a control circuit and a control signal port, wherein the control circuit is connected in series between the VDD power supply terminal of the synchronous rectification chip and the control signal port, and the control circuit is provided with a power input terminal Vin for connecting to an input voltage; the control signal port is used for connecting to a control signal, and the control circuit is used for supplying power to the synchronous rectification chip according to the control signal.

[0009] Optionally, when the control signal connected to the control signal port is at a low level, the control circuit supplies power to the VDD of the synchronous rectifier chip, and the synchronous rectifier chip works; when the control signal connected to the control signal port is at a high level, the control circuit stops supplying power to the synchronous rectifier chip VDD, and the synchronous rectifier chip does not work.

[0010] Optionally, the control circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first transistor Q1, a second transistor Q2, a first optical coupler OC1, a power input port Vin, an output power interface Vo, and an output ground port -Vo;

[0011] The emitter of the first transistor Q1 is connected to the VDD power supply end of the synchronous rectification chip, the collector of the first transistor Q1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to the output power interface Vo, the base of the first transistor Q1 is connected to one end of the second resistor R2, one end of the third resistor R3 and the collector of the second transistor Q2, the other end of the second resistor R2 is connected to the output power interface Vo, the emitter of the second transistor Q2 is connected to the output ground port -Vo, the base of the second transistor Q2 is connected to the other end of the third resistor R3, one end of the fourth resistor R4 and one end of the fifth resistor R5, the other end of the fourth resistor R4 is connected to the emitter of the secondary transistor of the first optical coupler OC1, the other end of the fifth resistor R5 is connected to the output ground port -Vo, the collector of the secondary transistor of the first optical coupler OC1 is connected to the output power interface Vo, the anode of the primary light emitting diode of the first optical coupler OC1 is connected to the power input port Vin, the cathode of the primary light emitting diode of the first optical coupler OC1 is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is connected to the control signal port.

[0012] Optionally, the control circuit also includes a diode D1 and a capacitor C1, the anode of the diode D1 is connected to the emitter of the first transistor Q1, one end of the capacitor C1, and the VDD power supply end of the synchronous rectification control chip, the cathode of the diode D1 is connected to the base of the first transistor Q1, one end of the resistor R2, one end of the resistor R3, and the collector of the second transistor; the other end of the capacitor C1 is connected to the output ground port -Vo.

[0013] Specifically, the capacitor C1 can filter out the ripple of the output power interface Vo and improve the working stability of the synchronous rectification chip. When the control signal port CD is grounded, the diode D1 can quickly discharge the energy of the capacitor C1 to achieve the purpose of quickly shutting down the synchronous rectification chip.

[0014] Optionally, in order to prevent the VDD power supply terminal voltage from being too high and causing current backflow to damage the first optocoupler OC1, the control circuit also includes a diode D2, the anode of the diode D2 is connected to the collector of the secondary transistor of the first optocoupler OC1, and the cathode of the diode D2 is connected to one end of the fourth resistor R4.

[0015] Optionally, the first transistor Q1 and the second transistor Q2 are NPN transistors.

[0016] In a third aspect, a bidirectional power supply is provided, comprising a main power circuit and a logic driving circuit for synchronous rectification of the bidirectional power supply as described in the first and second aspects.

[0017] Compared with the prior art, the beneficial effects of the present application are as follows: since the synchronous rectifier chip is very prone to accidental touch when the bidirectional power supply is working in reverse, the present application adopts a solution of using the CD port to control the power supply of the synchronous rectifier chip. When the bidirectional power supply is working in reverse, the CD port is controlled to be grounded, and the control circuit stops supplying power to the synchronous rectifier control chip, so that the bidirectional power supply does not supply power to the synchronous rectifier chip when working in reverse, thereby achieving a stable reverse working state. This circuit can be applied to a bidirectional power supply with synchronous rectification; by adding capacitor C1 and diode D1, the ripple of the output power interface Vo can be filtered out, and the working stability of the synchronous rectifier chip can be improved. When the control signal port CD is grounded, the diode D1 can quickly discharge the energy of capacitor C1, thereby achieving the purpose of quickly shutting down the synchronous rectifier chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a principle block diagram of the logic drive circuit of the utility model.

[0019] Figure 2 It is a principle block diagram of the logic driving circuit described in the first embodiment.

[0020] Figure 3 This is another principle block diagram of the logic driving circuit described in the first embodiment.

[0021] Figure 4 It is a principle block diagram of the logic driving circuit described in the second embodiment. DETAILED DESCRIPTION

[0022] The present invention and its beneficial effects will be further described in detail below in conjunction with specific implementation methods and drawings of the specification; however, the specific implementation methods of the present invention are not limited thereto.

[0023] First embodiment

[0024] like Figure 1 As shown, it is a structural block diagram of the logic driving circuit of the bidirectional power supply synchronous rectification shown in this embodiment. In this embodiment, a logic driving circuit of the bidirectional power supply synchronous rectification is provided, including a synchronous rectification chip, a control circuit and a control signal port. The control circuit is connected in series between the VDD power supply terminal of the synchronous rectification chip and the control signal port. The control circuit is provided with a power input terminal Vin for connecting to the input voltage; the control signal port is used for connecting to the control signal, and the control circuit is used for supplying power to the synchronous rectification chip according to the control signal.

[0025] Specifically, when the bidirectional power supply is working in the reverse direction, the control signal connected to the control signal port is at a low level, that is, the control signal port is grounded, and the control circuit supplies power to the VDD of the synchronous rectifier chip, and the synchronous rectifier chip works. When the bidirectional power supply is working in the forward direction, the control signal connected to the control signal port is at a high level, that is, the control signal port is suspended or connected to a high level, and the control circuit stops supplying power to the synchronous rectifier chip VDD, and the synchronous rectifier chip does not work. Figure 2 As shown, this embodiment includes a synchronous rectification chip, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first transistor Q1, a second transistor Q2, a first optical coupler OC1, a control signal port CD, a power input port Vin, an output power interface Vo, and an output ground port -Vo;

[0026] The emitter of the first transistor Q1 is connected to the VDD power supply end of the synchronous rectification chip, the collector of the first transistor Q1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to the output power interface Vo, the base of the first transistor Q1 is connected to one end of the second resistor R2, one end of the third resistor R3 and the collector of the second transistor Q2, the other end of the second resistor R2 is connected to the output power interface Vo, the emitter of the second transistor Q2 is connected to the output ground port -Vo, the base of the second transistor Q2 is connected to the other end of the third resistor R3, one end of the fourth resistor R4 and one end of the fifth resistor R5, the other end of the fourth resistor R4 is connected to the emitter of the secondary transistor of the first optical coupler OC1, the other end of the fifth resistor R5 is connected to the output ground port -Vo, the collector of the secondary transistor of the first optical coupler OC1 is connected to the output power interface Vo, the anode of the primary light emitting diode of the first optical coupler OC1 is connected to the power input port Vin, the cathode of the primary light emitting diode of the first optical coupler OC1 is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is connected to the control signal port.

[0027] The working principle of this embodiment is: when the control signal port CD is grounded, the primary side light emitting diode of the first optical coupler OC1 has a forward current After reaching the light-emitting threshold, the secondary transistor of the first optocoupler OC1 is turned on. At this time, the base voltage of the second transistor Q2 is about After reaching the conduction threshold, the second transistor Q2 is turned on. At this time, the base voltage of the first transistor Q1 is approximately -Vo, and the first NPN transistor Q1 is turned off. At this time, there is no voltage at the VDD power supply end, and the synchronous rectification chip does not work.

[0028] When the control signal port CD is suspended or set to a high level, the primary side light emitting diode of the first optocoupler OC1 does not emit light, the secondary side transistor of the first optocoupler OC1 is cut off, at this time the base voltage of the second transistor Q2 is approximately -Vo, the second NPN transistor Q2 is cut off, at this time the base voltage of the first NPN transistor Q1 is approximately After reaching the conduction threshold, the first transistor Q1 is turned on and the voltage at the VDD power supply terminal is approximately Vo-V loss-Q1 , the synchronous rectification chip works.

[0029] like Figure 3 As shown, in this embodiment, the control circuit also includes a capacitor C1 and a diode D1; one end of the capacitor C1 is connected to the VDD power supply end of the synchronous rectifier chip, and the other end is connected to the output ground port -Vo, the anode of the diode D1 is connected to the collector of the first transistor Q1, and the cathode is connected to the base of the first transistor Q1.

[0030] The capacitor C1 can filter out the ripple of the power interface Vo and improve the working stability of the synchronous rectification chip. When the control signal port CD is grounded, the diode D1 can quickly discharge the energy of the first capacitor C1 to achieve the purpose of quickly shutting down the synchronous rectification chip.

[0031] Second embodiment

[0032] like Figure 4 As shown, this embodiment is based on the first embodiment. In order to prevent the voltage at the VDD power supply end from being too high and causing current backflow to damage the first optocoupler OC1, a diode D2 is added. The diode D2 is connected in series between the fourth resistor R4 and the secondary transistor of the first optocoupler OC1. The anode of the diode D2 is connected to the drain of the secondary transistor of the first optocoupler OC1, and the cathode is connected to one end of the fourth resistor R4.

[0033] According to the disclosure and teaching of the above description, the technicians in the field of the utility model can also change and modify the above implementation. Therefore, the utility model is not limited to the above specific implementation, and any obvious improvement, replacement or modification made by the technicians in this field on the basis of the utility model belongs to the protection scope of the utility model. In addition, although some specific terms are used in this specification, these terms are only for the convenience of explanation and do not constitute any limitation to the utility model.

Claims

1. A logic driving circuit for bidirectional power supply synchronous rectification, characterized in that: It includes a synchronous rectification chip, a control circuit and a control signal port, wherein the control circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first transistor Q1, a second transistor Q2, a first optical coupler OC1, a power input port Vin, an output power interface Vo, and an output ground port -Vo; The emitter of the first transistor Q1 is connected to the VDD power supply end of the synchronous rectification chip, the collector of the first transistor Q1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to the output power interface Vo, the base of the first transistor Q1 is connected to one end of the second resistor R2, one end of the third resistor R3 and the collector of the second transistor Q2, the other end of the second resistor R2 is connected to the output power interface Vo, the emitter of the second transistor Q2 is connected to the output ground port -Vo, the base of the second transistor Q2 is connected to the other end of the third resistor R3, one end of the fourth resistor R4 and one end of the fifth resistor R5, the other end of the fourth resistor R4 is connected to the emitter of the secondary transistor of the first optical coupler OC1, the other end of the fifth resistor R5 is connected to the output ground port -Vo, the collector of the secondary transistor of the first optical coupler OC1 is connected to the output power interface Vo, the anode of the primary light emitting diode of the first optical coupler OC1 is connected to the power input port Vin, the cathode of the primary light emitting diode of the first optical coupler OC1 is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is connected to the control signal port.

2. A logic driving circuit for bidirectional power supply synchronous rectification, characterized in that: It includes a synchronous rectification chip, a control circuit and a control signal port. The control circuit is connected in series between the VDD power supply terminal of the synchronous rectification chip and the control signal port. The control circuit is provided with a power input terminal Vin for connecting to the input voltage. The control signal port is used for connecting to the control signal. The control circuit is used for supplying power to the synchronous rectification chip according to the control signal.

3. The logic driving circuit for bidirectional power supply synchronous rectification according to claim 2, characterized in that: When the control signal connected to the control signal port is at a low level, the control circuit supplies power to the VDD of the synchronous rectifier chip, and the synchronous rectifier chip works. When the control signal connected to the control signal port is at a high level, the control circuit stops supplying power to the synchronous rectifier chip VDD, and the synchronous rectifier chip does not work.

4. The logic driving circuit for bidirectional power supply synchronous rectification according to claim 2, characterized in that: The control circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first transistor Q1, a second transistor Q2, a first optical coupler OC1, a power input port Vin, an output power interface Vo, and an output ground port -Vo; The emitter of the first transistor Q1 is connected to the VDD power supply end of the synchronous rectification chip, the collector of the first transistor Q1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to the output power interface Vo, the base of the first transistor Q1 is connected to one end of the second resistor R2, one end of the third resistor R3 and the collector of the second transistor Q2, the other end of the second resistor R2 is connected to the output power interface Vo, the emitter of the second transistor Q2 is connected to the output ground port -Vo, the base of the second transistor Q2 is connected to the other end of the third resistor R3, one end of the fourth resistor R4 and one end of the fifth resistor R5, the other end of the fourth resistor R4 is connected to the emitter of the secondary transistor of the first optical coupler OC1, the other end of the fifth resistor R5 is connected to the output ground port -Vo, the collector of the secondary transistor of the first optical coupler OC1 is connected to the output power interface Vo, the anode of the primary light emitting diode of the first optical coupler OC1 is connected to the power input port Vin, the cathode of the primary light emitting diode of the first optical coupler OC1 is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is connected to the control signal port.

5. The logic driving circuit for bidirectional power supply synchronous rectification according to claim 4, characterized in that: The control circuit also includes a diode D1 and a capacitor C1, the anode of the diode D1 is connected to the emitter of the first transistor Q1, one end of the capacitor C1, and the VDD power supply end of the synchronous rectification control chip, the cathode of the diode D1 is connected to the base of the first transistor Q1, one end of the resistor R2, one end of the resistor R3, and the collector of the second transistor; the other end of the capacitor C1 is connected to the output ground port -Vo.

6. The logic driving circuit for bidirectional power supply synchronous rectification according to claim 5, characterized in that: The control circuit further includes a diode D2, an anode of the diode D2 is connected to the collector of the secondary transistor of the first optical coupler OC1, and a cathode of the diode D2 is connected to one end of the fourth resistor R4.

7. The logic driving circuit for bidirectional power supply synchronous rectification according to any one of claims 4 to 6, characterized in that: The first transistor Q1 and the second transistor Q2 are NPN transistors.

8. A bidirectional power supply, characterized in that: It comprises a main power circuit and a logic driving circuit for synchronous rectification of a bidirectional power supply as claimed in any one of claims 1 to 7.

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