System and method for high voltage protection of powered devices

• US 20070263332A1
• Filed: 05/11/2006
• Published: 11/15/2007
• Est. Priority Date: 05/11/2006
• Status: Abandoned Application

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Apfel, Russell
• Application Number:
  US11/433,221
• Publication Number:
  US 20070263332A1
• Time in Patent Office: Days
• US Class Current: 361/90
• CPC Class Codes: H02H 9/041 using a short-circuiting device

Abstract

An integrated circuit includes a rectifier circuit, at least one low power element, and a power protection element. The rectifier circuit includes two inputs to receive an input power supply and includes two outputs to provide a rectified power supply related to the input power supply. The low-power circuit element is coupled between the two outputs. The power protection element is coupled between the two output terminals. In a first mode of operation, the power protection element presents a high impedance to the two output terminals. In a second mode of operation, the power protection element has a first power protection characteristic. In a third mode of operation, the power protection element has a second power protection characteristic. The power protection element is adapted to shut down the low-power circuit element when in the third mode of operation.

Claims

1. An integrated circuit comprising:

a rectifier circuit having two inputs to receive an input power supply and having two outputs to provide a rectified power supply related to the input power supply;

at least one low-power circuit element coupled between the two outputs; and

a power protection element coupled between the two output terminals, wherein, in a first mode of operation, the power protection element presents a high impedance to the two output terminals, in a second mode of operation, the power protection element has a first power protection characteristic, and in a third mode of operation, the power protection element has a second power protection characteristic, the power protection element to shut down the at least one low-power circuit element when in the third mode of operation.

2. The integrated circuit of claim 1, wherein the power protection element comprises an over-voltage threshold component to detect an over-voltage condition and a switch coupled to the over-voltage threshold component to clamp the rectified power supply to a voltage level that is below a threshold voltage level.

3. The integrated circuit of claim 1, wherein the power protection element comprises two switches adapted to activate asynchronously in response to a signal to clamp the rectified power supply to a reduced voltage level.

4. The integrated circuit of claim 1, wherein the power protection element comprises a silicon controlled rectifier.

5. The integrated circuit of claim 1, wherein the power protection element further comprises active logic to generate a fault protection signal provided to the at least one low-power circuit element when in the third mode of operation.

6. The integrated circuit of claim 5, wherein the fault protection signal comprises a shut down signal to deactivate the at least one low-power circuit element.

7. The integrated circuit of claim 1, wherein the power protection element is at a higher voltage in the second mode of operation than in the third mode of operation.

8. The integrated circuit of claim 7, wherein in the second mode of operation, the higher voltage is greater than 55 volts and wherein the power protection element has a current level less than one Ampere.

9. The integrated circuit of claim 7, wherein in the third mode of operation, the power protection element has a voltage level less than ten volts and a current level greater than half an Ampere.

10. The integrated circuit of claim 7, wherein the power protection element changes from the second mode of operation to the first mode of operation after a current level of the power protection element falls below a threshold current level.

11. The integrated circuit of claim 1, wherein the second power protection characteristic comprises a lower impedance than the first power protection characteristic.

12. A method comprising:

receiving an input voltage supply at a pair of terminals;

detecting an over-voltage condition related to the input voltage supply using an over-voltage protection element; and

concurrently shunting the input voltage supply between the pair of terminals and generating a shut off signal to associated circuitry in response to the over-voltage condition using the over-voltage protection element.

13. The method of claim 12, wherein detecting an over-voltage condition comprises:

detecting a voltage at a silicon controlled rectifier of an integrated circuit, the integrated circuit having at least one low-voltage component; and

maintaining a first transistor and a second transistor in an off state when the voltage is less than a voltage protection threshold.

14. The method of claim 13, wherein shunting the input voltage supply comprises:

activating the first transistor and the second transistor to shunt the voltage to a lower voltage level when the voltage exceeds the voltage protection threshold; and

generating a fault protection signal to shut off power to the at least one low-voltage component.

15. The method of claim 14, wherein activating the first transistor and the second transistor comprises activating the first transistor before activating the second transistor.

16. The method of claim 12, wherein detecting the over-voltage condition comprises:

receiving an input voltage from a powered network at an integrated circuit including the over-voltage protection element;

rectifying the input voltage to produce a rectified voltage; and

detecting a voltage level of the rectified voltage.

17. An integrated circuit comprising:

input terminals to receive an input power supply;

at least one low-power circuit element coupled between the input terminals; and

a power protection element coupled between the input terminals to detect a power characteristic of the input power supply, the power protection element to shunt excess power between the input terminals and to shut off power to the at least one low-power circuit element when the power characteristic exceeds a threshold power level.

18. The integrated circuit of claim 17, wherein the power characteristic comprises a voltage level in excess of a threshold voltage level.

19. The integrated circuit of claim 17, wherein the power characteristic comprises a current level that is greater than a threshold current level.

20. The integrated circuit of claim 17, wherein the power protection element comprises a silicon controlled rectifier circuit.

21. The integrated circuit of claim 17, wherein the input terminals comprise a first power supply terminal and a second power supply terminal and wherein the power protection element comprises:

a resistor having a first terminal coupled to the second power supply terminal, and a second terminal;

a diode circuit having an anode terminal coupled to the second terminal of the resistor and a cathode terminal coupled to the first power supply terminal; and

a transistor having a first terminal coupled to the first power supply terminal, a second terminal coupled to the second power supply terminal, and a control terminal coupled to the second terminal of the resistor, the transistor providing a current path between the first power supply terminal and the second power supply terminal when active.

22. The integrated circuit of claim 17, wherein the input terminals are coupled to a powered network.

23. A method comprising:

receiving an input power supply at a pair of terminals, the pair of terminals including a first terminal and a second terminal;

detecting a power level of the input power supply using a power protection element of an integrated circuit, the integrated circuit having at least one low-power component;

activating the power protection element to shunt the input power supply between the first terminal and the second terminal when the power level exceeds a threshold power level; and

substantially reducing a power supply to the at least one low-power component when the power level exceeds the threshold power level.

24. The method of claim 23, wherein the power protection element comprises a first transistor and a second transistor, the first transistor and the second transistor coupled between the first terminal and the second terminal, the method further comprising:

maintaining the first transistor and the second transistor in an off state when the power level is less than the threshold power level.

25. The method of claim 24, wherein activating the power protection element comprises activating the first transistor before activating the second transistor.