Circuit for driving synchronous rectifier device with false turn on prevention

Patent metadata

Field	Value
Publication number	US-11245327-B2
Application number	US-202016851057-A
Country	US
Kind code	B2
Filing date	Apr 16, 2020
Priority date	Jun 4, 2019
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

A driving circuit for driving a synchronous rectifier device. The driving circuit may include a controllable clamping circuit having a first terminal coupled to a sensing terminal of the driving circuit, a second terminal coupled to a reference ground terminal of the driving circuit, a third terminal coupled to a driving terminal of the driving circuit, and a control terminal configured to receive a supply indication signal indicative of a voltage potential at a supply terminal of the driving circuit. The third terminal of the controllable clamping circuit may be connected to the second terminal of the controllable clamping circuit when the supply indication signal indicates that the voltage potential at the supply terminal has not been established to maintain the synchronous rectifier device off.

First claim

What is claimed is:

1. A driving circuit for driving a synchronous rectifier device, comprising:
a controllable clamping circuit, having a first terminal coupled to a sensing terminal of the driving circuit, a second terminal coupled to a reference ground terminal of the driving circuit, a third terminal coupled to a driving terminal of the driving circuit, and a control terminal configured to receive a supply indication signal indicative of a voltage potential at a supply terminal of the driving circuit; wherein
the controllable clamping circuit is configured to connect the third terminal of the controllable clamping circuit to the second terminal of the controllable clamping circuit when the supply indication signal indicates that the voltage potential at the supply terminal has not been established; and wherein
the controllable clamping circuit further comprises:
a controllable voltage regulation module, comprising: a controllable current source structure, having a supply input terminal coupled to the first terminal of the controllable clamping circuit, a control terminal configured to receive the supply indication signal, and an output terminal, wherein when an output voltage potential at the output terminal of the controllable current source structure is lower than a predetermined voltage and the supply indication signal indicates that the voltage potential at the supply terminal has not been established, the controllable current source structure is configured to provide a current to its output terminal, and wherein when the output voltage potential at the output terminal of the controllable current source structure reaches the predetermined voltage or the supply indication signal indicates that the voltage potential at the supply terminal has been established, the controllable current source structure is further configured to stop providing the current to its output terminal; and a controllable energy storage structure, having a first terminal coupled to the output terminal of the controllable current source structure, a second terminal coupled to the second terminal of the controllable clamping circuit, and a control terminal configured to receive the supply indication signal, wherein when the supply indication signal indicates that the voltage potential at the supply terminal has not been established, the controllable energy storage structure is configured to receive the current from the controllable current source structure and store energy to provide the predetermined voltage at the first terminal of the controllable energy storage structure, and wherein when the supply indication signal indicates that the voltage potential at the supply terminal has been established, the controllable energy storage structure is further configured to release energy.

2. The driving circuit of claim 1 , wherein
the controllable clamping circuit is configured to disconnect the third terminal of the controllable clamping circuit from the second terminal of the controllable clamping circuit when the supply indication signal indicates that the voltage potential at the supply terminal has been established.

3. The driving circuit of claim 1 , wherein the sensing terminal of the driving circuit is coupled to a first terminal of the synchronous rectifier device, and wherein the reference ground terminal of the driving circuit is coupled to a second terminal of the synchronous rectifier device, and wherein the driving terminal of the driving circuit is coupled to a control terminal of the synchronous rectifier device.

4. The driving circuit of claim 1 , wherein the controllable clamping circuit further comprises:
a controllable clamping switch, having a first terminal coupled to the second terminal of the controllable clamping circuit, a second terminal coupled to the third terminal of the controllable clamping circuit, and a control terminal coupled to the output terminal of the controllable current source structure, wherein the predetermined voltage is higher than a turn-on threshold of the controllable clamping switch.

5. The driving circuit of claim 4 , wherein the controllable clamping switch further comprises a switch device of a low rated operating voltage and of a low turn-on threshold.

6. The driving circuit of claim 1 , wherein the controllable current source structure further comprises:
a single direction conductive device, having a first terminal coupled to the supply input terminal of the controllable current source structure, and a second terminal, wherein the single direction conductive device is conductive from the first terminal to the second terminal and is reversely blocked from the second terminal to the first terminal; a first controllable switching device, having a control terminal, a first terminal coupled to the second terminal of the single direction conductive device, and a second terminal coupled to the output terminal of the controllable current source structure;
a second controllable switching device, having a control terminal configured to receive the supply indication signal, a first terminal coupled to the control terminal of the first controllable switching device, and a second terminal coupled to the second terminal of the controllable clamping circuit;
a resistive device, having a first terminal coupled to the supply input terminal of the controllable current source structure, and a second terminal coupled to the control terminal of the first controllable switching device; and
a voltage stabilizer, coupled between the control terminal of the first controllable switching device and the second terminal of the controllable clamping circuit, and is configured to stabilize a voltage at the control terminal of the first controllable switching device at a preset voltage value.

7. The driving circuit of claim 6 , wherein the second controllable switching device is turned off when the supply indication signal indicates that the voltage potential at the supply terminal has not been established, and wherein the second controllable switching device is turned on when the supply indication signal indicates that the voltage potential at the supply terminal has been established.

8. The driving circuit of claim 1 , wherein the controllable energy storage structure further comprises:
a capacitive energy storage device, having a first terminal coupled to the output terminal of the controllable current source structure, and a second terminal coupled to the second terminal of the controllable clamping circuit; and
an energy storage control switch, having a first terminal coupled to the output terminal of the controllable current source structure, a second terminal coupled to the second terminal of the controllable clamping circuit, and a control terminal configured to receive the supply indication signal.

9. The driving circuit of claim 8 , wherein the energy storage control switch is turned off when the supply indication signal indicates that the voltage potential at the supply terminal has not been established, and wherein the energy storage control switch is turned on when the supply indication signal indicates that the voltage potential at the supply terminal has been established.

10. The driving circuit of claim 1 , further comprising:
a high-voltage sustain module, coupled between the first terminal of the synchronous rectifier device and the first terminal of the controllable clamping circuit, and configured to clamp a voltage potential at an output terminal of the high-voltage sustain module at a designed safe voltage.

11. The driving circuit of claim 10 , wherein the high-voltage sustain module has a breakdown voltage higher than a maximum voltage potential value of the voltage potential at

Assignees

• Chengdu Monolithic Power Sys

Inventors

• Feng Lin
• Chen Yuedong

Classifications

• H02M7/217

  using semiconductor devices only · CPC title

• H02M7/12

  using discharge tubes with control electrode or semiconductor devices with control electrode · CPC title

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• H02M1/0045

  Converters combining the concepts of switch-mode regulation and linear regulation, e.g. linear pre-regulator to switching converter, linear and switching converter in parallel, same converter or same transistor operating either in linear or switching mode · CPC title

• H02M1/36 Primary

  Means for starting or stopping converters · CPC title