Power supply protection circuit

Patent metadata

Field	Value
Publication number	US-10079539-B2
Application number	US-201715421951-A
Country	US
Kind code	B2
Filing date	Feb 1, 2017
Priority date	Feb 1, 2017
Publication date	Sep 18, 2018
Grant date	Sep 18, 2018

Abstract

A protection circuit and a method for a high voltage switching regulator is presented. A power supply comprising a switching converter for providing an output voltage is provided. The switching converter is comprised of a first power switch coupled to a second power switch via a switching node, and a driver coupled to the first and second power switches. There is a protection circuit comprised of a first isolation switch coupled to a second isolation switch and a first driver for driving the first isolation switch, and a second driver for driving the second isolation switch. The circuit and method may comprise turning off both the first isolation switch and the second isolation switch when the first power switch and the second power switch are both turned off. This isolates a low voltage domain from a high voltage domain. This prevents current leakages from occurring during switching dead times.

First claim

What is claimed is:

1. A power supply comprising:
a switching converter for providing an output voltage, the switching converter comprising a first power switch coupled to a second power switch via a switching node, and a driver coupled to the first and second power switches; the driver being adapted to operate the first and second power switches with a switching cycle having a switching dead-time during which both the first and the second power switches are turned off; and
a protection circuit comprising a first isolation switch coupled to a second isolation switch; a first driver for driving the first isolation switch, and a second driver for driving the second isolation switch; wherein the first driver is configured to provide a first voltage to turn off the first isolation switch during the switching dead-time; and wherein the second driver is configured to provide a second voltage to turn off the second isolation switch during the switching dead-time.

2. The power supply as claimed in claim 1 , wherein the first isolation switch comprises a first transistor having a first source terminal and a first drain terminal, and wherein the second isolation switch comprises a second transistor comprising a second source terminal and a second drain terminal, wherein the first drain terminal is connected to the second drain terminal; and wherein the first source terminal is connected to the switching node.

3. The power supply as claimed in claim 2 , wherein the first transistor is a NMOS transistor and wherein the second transistor is a NMOS transistor.

4. The power supply as claimed in claim 2 , wherein the first transistor is a PMOS transistor and wherein the second transistor is a PMOS transistor.

5. The power supply as claimed in claim 1 , comprising a bootstrap circuit for providing a bootstrap voltage; the bootstrap circuit being coupled to both the first power switch and to the first driver.

6. The power supply as claimed in claim 1 , comprising a comparator comprising a first input coupled to a reference voltage, a second input coupled to the second isolation switch and an output coupled to the driver of the switching converter.

7. The power supply as claimed in claim 1 , wherein the first isolation switch comprises a first transmission gate and wherein the second isolation switch comprises a second transmission gate.

8. The power supply as claimed in claim 1 , wherein the power supply is a high voltage power supply, and wherein the switching node provides a voltage varying between a negative value and a positive value.

9. A method of operating a power supply comprising a first power switch coupled to a second power switch via a switching node, wherein the first power switch is provided between an input and the switching node and wherein the second power switch is provided between the switching node and a ground; the method comprising the steps of:
operating the first and second power switches with a switching cycle having a switching dead-time during which both the first and the second power switches are turned off;
providing a protection circuit comprising a first isolation switch coupled to a second isolation switch; a first driver for driving the first isolation switch, and a second driver for driving the second isolation switch;
wherein the first driver is configured to provide a first voltage to turn off the first isolation switch during the switching dead-time; and wherein the second driver is configured to provide a second voltage to turn off the second isolation switch during the switching dead-time.

10. The method as claimed in claim 9 , comprising turning on both the first isolation switch and the second isolation switch when the second power switch is turned on.

11. The method as claimed in claim 9 , wherein the first isolation switch comprises a first transistor having a first source terminal and a first drain terminal, and wherein the second isolation switch comprises a second transistor comprising a second source terminal and a second drain terminal, wherein the first drain terminal is connected to the second drain terminal; and wherein the first source terminal is connected to the switching node.

12. The method as claimed in claim 9 , wherein the power supply comprises a bootstrap circuit for providing a bootstrap voltage; the bootstrap circuit being coupled to both the first power switch and to the first driver.

13. The method as claimed in claim 9 , wherein the protection circuit comprises a comparator, the method comprising comparing a source voltage of the second isolation switch with a reference voltage and generating an error signal based on the comparison.

14. A protection circuit for use with a switching converter comprising a first power switch coupled to a second power switch via a switching node, and a driver coupled to the first and second power switches;
the driver being adapted to operate the first and second power switches with a switching cycle having a switching dead-time during which both the first and the second power switches are turned off;
the protection circuit comprising a first isolation switch coupled to a second isolation switch; a first driver for driving the first isolation switch, and a second driver for driving the second isolation switch;
wherein the first driver is configured to provide a first voltage to turn off the first isolation switch during the switching dead-time;
and wherein the second driver is configured to provide a second voltage to turn off the second isolation switch during the switching dead-time.

15. The protection circuit as claimed in claim 14 , wherein the first isolation switch comprises a first transistor having a first source terminal and a first drain terminal, and wherein the second isolation switch comprises a second transistor comprising a second source terminal and a second drain terminal, wherein the first drain is connected to the second drain; and wherein the first source terminal is connected to the switching node.

16. The protection circuit as claimed in claim 14 comprising a bootstrap circuit for providing a bootstrap voltage; the bootstrap circuit being coupled to both the first power switch and to the first driver.

17. The protection circuit as claimed in claim 14 , comprising a comparator comprising a first input coupled to a reference voltage, a second input coupled to the second isolation switch and an output coupled to the driver of the switching converter.

Assignees

• Powerventure Semiconductor Ltd
• Dialog Semiconductor Uk Ltd

Inventors

• Hsiao Yuan Wen
• Wu Chang Ching
• Huang Chi-Chia
• Hung Der Ju

Classifications

• H02M1/32 Primary

  Means for protecting converters other than automatic disconnection · CPC title

• H02M3/158 Primary

  including plural semiconductor devices as final control devices for a single load · CPC title

• H02M3/156

  with automatic control of output voltage or current, e.g. switching regulators · CPC title

• H02M3/1588

  comprising at least one synchronous rectifier element (H02M3/1582, H02M3/1584 take precedence) · CPC title

• Y02B70/10

  Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes · CPC title