A POWER SWITCH DRIVE CIRCUIT WITH BUILT-IN POWER SUPPLY CAPACITOR

• US 20190312576A1
• Filed: 06/02/2017
• Published: 10/10/2019
• Est. Priority Date: 06/02/2017
• Status: Active Grant

• Current Assignee: Shenzhen Winsemi Microelectronics Co., Ltd
• Original Assignee: Shenzhen Winsemi Microelectronics Co., Ltd
• Inventors: SONG, Lijun
• Granted Patent: US 10,566,970 B2
• Time in Patent Office: Days
• CPC Class Codes: H02M 1/08 Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H03K 17/04123 in field-effect transistor switches
• CPC Class Codes: H03K 17/063 in field-effect transistor switches
• CPC Class Codes: H03K 17/223 in field-effect transistor switches
• CPC Class Codes: H03K 17/6877 the control circuit comprising active elements different from those used in the output circuit
• CPC Class Codes: H03K 2017/6875 using self-conductive, depletion FETs
• CPC Class Codes: H03K 2217/0036 Means reducing energy consumption
• CPC Class Codes: H03K 2217/0081 Power supply means, e.g. to the switch driver

Abstract

A power switch drive circuit with a built-in power supply capacitor, when the power switch (M1) reaches the turn-on threshold, it is discharged through the power supply capacitor (Cvcc) to turn on the power switch (M1), thereby saving the charge requirement on the power supply capacitor (Cvcc), and enabling a small-capacity power supply capacitor (Cvcc) to realize power switch (M1) driving. At the same time, the power supply capacitor (Cvcc) can be designed in an integrated circuit to improve reliability and reduce costs, therefore, it can solve the problem that the capacity of the power supply capacitor is too large to be able to be designed on the integrated circuit, which results in a large occupied space and an increased cost.

Claims

1. A power switch drive circuit with a built-in power supply capacitor, the power switch drive circuit comprises a drive unit, the drive unit comprises a power switch, a junction field effect transistor, a field effect transistor control circuit, and a drive control circuit, the drive unit also comprises:

a logic circuit, a power supply diode, a first switch module, a second switch module, a third switch module, and a power supply capacitor;

an output end of the field effect transistor control circuit is connected with a gate of the junction field effect transistor, a drain of the junction field effect transistor and an input end of the power switch are connected with a power supply unit, a source of the junction field effect transistor, an input end of the first switch module, a connection end of the drive control circuit, and an anode of the power supply diode are connected in common;

a first control end of the drive control circuit is connected with a controlled end of the first switch module, a second control end of the drive control circuit is connected with a controlled end of the second switch module, a cathode of the power supply diode and a first end of the power supply capacitor, and an input end of the second switch module are connected in common, an output end of the first switch module, an output end of the second switch module, an input end of the third switch module, and a controlled end of the power switch are connected in common, a second end of the power supply capacitor and an output end of the third switch module are grounded, a control end of the logic circuit is connected with a controlled end of the drive control circuit, an output of the logic circuit is connected with a controlled end of the third switch module, an connection end of the logic circuit and an output end of the power switch are connected in common with an output unit;

the direct current output by the power supply unit is configured to not only charge the power supply capacitor but also supply power to the power switch;

the drive control circuit is configured to control the first switch module to be turned on when the logic circuit outputs a turn-on control signal, and the drive control circuit is configured to control the first switch module to be turned off and the second switch module to be turned on when the power switch reaches a turn-on threshold such that the power supply capacitor is discharged to turn on the power switch; and

the third switch module is configured to be turned on when the logic circuit outputs a turn-off control signal, and the drive control circuit is configured to control the second switch module to be turned off, so that the power supply capacitor is charged and the power switch is turned off.

2. The power switch drive circuit of claim 1, wherein the power supply comprises:

an alternating current power supply, a first diode, a second diode, a third diode, a fourth diode and the bus capacitor;

a first output end of the alternating current power source, an anode of the first diode and a cathode of the third diode are connected in common, a second output end of the alternating current power source, a cathode of the fourth diode D4 and an anode of the second diode are connected in common, a cathode of the first diode, a cathode of the second diode and the first end of the bus capacitor are connected in common and serves as an output end of the power supply unit, an anode of the third diode, an anode of the fourth diode and a second end of the bus capacitor are connected in common.

3. The power switch drive circuit of claim 2, wherein the output unit comprises:

a sampling resistor, a inductor, an output capacitor, a freewheel diode, and load;

a first end of the sampling resistor and a cathode of the freewheel diode are connected to serve as an input end of the output unit, a second end of the sampling resistor and a first end of the inductor are grounded, and a second end of the inductor, a first end of the output capacitor and a first end of the load are connected in common, an anode of the freewheel diode, a second end of the output capacitor and a second end of the load are connected in common and is connected with a second end of the bus capacitor.

4. The power switch drive circuit of claim 1, wherein the first switch module is a triode or a field effect transistor;

a base, a collector and an emitter of the triode act as a controlled end, an input end and an output end of the first switch module respectively.

a gate, a drain and a source of the filed effect transistor act as a controlled end, an input end and an output end of the first switch module respectively.

5. The power switch drive circuit of claim 1, wherein the second switch module is a triode or a field effect transistor;

a base, a collector and an emitter of the triode act as a controlled end, an input end and an output end of the second switch module respectively.

a gate, a drain and a source of the filed effect transistor act as a controlled end, an input end and an output end of the second switch module respectively.

6. The power switch drive circuit of claim 1, wherein the third switch module is a triode or a field effect transistor;

A base, a collector and an emitter of the triode act as a controlled end, an input end and an output end of the third switch module respectively.

a gate, a drain and a source of the filed effect transistor act as a controlled end, an input end and an output end of the third switch module respectively