High-voltage, bidirectional protection circuits and methods

Patent metadata

Field	Value
Publication number	US-11962145-B2
Application number	US-202217744290-A
Country	US
Kind code	B2
Filing date	May 13, 2022
Priority date	Jun 6, 2021
Publication date	Apr 16, 2024
Grant date	Apr 16, 2024

Abstract

Systems and methods herein use a sensing circuit to detect an overvoltage at a voltage node as a drain current. A current-mode comparator converts the detected current into a control signal, which is provided to a control circuit. The control circuit uses the control signal cut of a bias current to turn off switches in a protection circuit to create a high-impedance electrical path between the voltage node and the to-be-protected voltage node.

First claim

What is claimed is:

1. An overvoltage protection method comprising:
using a sensing circuit that, in response to an overvoltage condition being present at a voltage node, detects a current;
using a current-mode comparator to convert the current to a control signal; and
using a control circuit that, in response receiving the control signal, turns off a set of switching devices that are coupled to a to-be-protected voltage node to create a high-impedance electrical path between the voltage node and the to-be-protected voltage node.

2. The overvoltage protection method according to claim 1 , wherein the overvoltage condition is a high positive or negative voltage outside of an operating voltage range of the to-be-protected voltage node.

3. The overvoltage protection method according to claim 1 , wherein the sensing circuit is a current sensing circuit and the control signal is a state signal that controls a set of bias currents.

4. The overvoltage protection method according to claim 1 , further comprising using a high-voltage resistor coupled to the voltage node to generate a drain current for a switch.

5. The overvoltage protection method according to claim 4 , further comprising using the current sensing circuit to detect the drain current that indicates the overvoltage condition at the voltage node.

6. The overvoltage protection method according to claim 5 , further comprising using the drain current as the control signal and using the control circuit as a bias current controller.

7. The overvoltage protection method according to claim 6 , wherein the bias current controller applies a bias current to the set of switching devices to turn them off to create the high-impedance electrical path.

8. A dual-polarity high-voltage protection circuit comprising:
a protection circuit coupled to a to-be-protected voltage node and an output voltage node;
a voltage sensing circuit that, in response to sensing an overvoltage condition present at the output voltage node, generates an output signal indicative of the overvoltage condition; and
a control circuit coupled to the voltage sensing circuit, the control circuit, in response to receiving the output signal, causes the protection circuit to assume a high impedance to isolate the to-be-protected voltage node from the overvoltage condition.

9. The circuit according to claim 8 , wherein the overvoltage condition is a high positive or negative voltage outside of an operating voltage range of the to-be-protected voltage node.

10. The circuit according to claim 9 , wherein the protection circuit comprises two sets of low-voltage switches, each set comprising opposing body diodes.

11. The circuit according to claim 10 , wherein the high positive voltage and the high negative voltage each have an amplitude that is lower than a breakdown voltage of a switch in the two sets of low-voltage switches.

12. The circuit according to claim 9 , wherein the operating voltage range is controlled by an output stage state of an operational amplifier that is coupled to the to-be-protected voltage node.

13. The circuit according to claim 12 , wherein the output stage state of the operational amplifier controls a voltage at the to-be-protected voltage node to be within the operating voltage range.

14. The circuit according to claim 9 , wherein the voltage sensing circuit comprises a switch coupled to the output voltage node, the switch generating the output signal in form of a current.

15. The circuit according to claim 14 , further comprising a current sensing circuit coupled to the voltage sensing circuit, the current sensing circuit, in response to receiving the current, outputs a state signal that controls a set of bias currents.

16. The circuit according to claim 15 , wherein the set of bias currents controls switches in the protection circuit to turn off.

17. The circuit according to claim 16 , wherein the current sensing circuit comprises a current-mode comparator coupled to the switch.

18. The circuit according to claim 17 , wherein, in response to the voltage sensing circuit not generating the output signal, the current-mode comparator generates a low-level signal to control the set of bias currents in a manner such as to cause the switches to turn on.

19. The circuit according to claim 10 , wherein a voltage drop between the to-be-protected voltage node and the output voltage node is determined by on-resistances of the switches and a load current flowing through the output voltage node.

20. A switch network for bidirectional high-voltage protection of a voltage node, the switch network comprising:
two sets of switches that each is coupled to a to-be-protected voltage node and an output voltage node, which in normal operation assumes a voltage within a voltage range;
a set of comparators that each is coupled to a switch in a third set of switches, respectively, and generates a low-level signal to control bias currents to cause the two sets of switches to turn on, such that the voltage drop between the to-be-protected voltage node and the output voltage node is determined by on-resistances of the two sets of switches and a load current flowing through the output voltage node; and
in response to the voltage at the output voltage node falling outside the voltage range, a drain current exceeding a current value causing a corresponding comparator in the set of comparators generating a high-level signal that causes the bias currents and, thus, the two sets of switches to turn off, thereby, creating a high-impedance path between the to-be-protected voltage node and the output voltage node, the voltage at the to-be-protected voltage node being controlled by an output stage state of an operational amplifier to be within the voltage range, the voltage at the output voltage node assuming values between a negative high voltage and a positive high voltage.

Assignees

• Maxim Integrated Products

Inventors

• Tanase Gabriel Eugen

Classifications

• H02H9/048 Primary

  Anti-latching or quenching devices, i.e. bringing the protection device back to its normal state after a protection action · CPC title

• G01D3/08

  with provision for safeguarding the apparatus, e.g. against abnormal operation, against breakdown · CPC title

• H02M1/32 Primary

  Means for protecting converters other than automatic disconnection · CPC title

• H02H9/04 Primary

  responsive to excess voltage (lightning arrestors H01C7/12, H01C8/04, H01G9/18, H01T) · CPC title

• H02H9/02

  responsive to excess current {(current limitation for voltage regulators G05F1/573; disconnection after limiting H02H3/025)} · CPC title