Transistor monitor for a multiphase circuit

• US 20050248360A1
• Filed: 05/04/2004
• Published: 11/10/2005
• Est. Priority Date: 05/04/2004
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Patel, Raoji A., Guenther, Robert A.
• Granted Patent: US 7,193,410 B2
• Time in Patent Office: Days
• US Class Current: 324/762.90
• CPC Class Codes: G01R 31/275 for testing individual semiconductor components within integrated circuits
• CPC Class Codes: G01R 31/40 Testing power supplies testing photovoltaic devices H02S50/10
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel

Abstract

A monitor system and method are described for sensing voltage changes in a plurality of transistors of a multiphase circuit comprising a sensor connected to each one of the plurality of transistors for measuring a voltage drop across the each one, a difference detector for comparing the voltage drop to a previous voltage drop attributable to the each one of the plurality of transistors, and a driver circuit for controlling a state of the plurality of transistors, wherein the driver circuit deactivates one or more of the plurality of transistors when the voltage drop varies from the previous voltage drop by a predefined amount.

Claims

1. A monitor for sensing voltage changes in a plurality of transistors of a multiphase circuit comprising:

a sensor connected to each one of said plurality of transistors for measuring a voltage drop across said each one;

a difference detector for comparing said voltage drop to a previous voltage drop attributable to said each one of said plurality of transistors; and

a driver circuit for controlling a state of said plurality of transistors, wherein said driver circuit deactivates one or more of said plurality of transistors when said voltage drop varies from said previous voltage drop by a predefined amount.

2. The monitor of claim 1 further comprising:

a memory for storing said measured voltage drops to become said previous voltage drop.

3. The monitor of claim 1 further comprising:

a delay circuit for delaying said comparing by said difference detector to avoid output load transients.

4. The monitor of claim 1 wherein said sensor is implemented using a sample-and-hold circuit.

5. The monitor of claim 1, wherein said plurality of transistors are implemented in said multiphase circuit in related pairs per phase.

6. The monitor of claim 5 further comprising:

deactivating one or more paired transistors corresponding to said deactivated one or more plurality of transistors.

7. The monitor of claim 1 further comprising:

a latch circuit for latching said deactivated one or more plurality of transistors in a deactivated state.

8. A method for monitoring performance of a plurality of transistors in a multiphase circuit comprising:

measuring a voltage across said plurality of transistors;

comparing said measured voltage against a prior measurement of said voltage;

deactivating one or more of said plurality of transistors when said measured voltage exceeds said prior measurement by a predetermined amount.

9. The method of claim 8 further comprising:

storing said measured voltages for comparison against new measured voltages.

10. The method of claim 8 further comprising:

delaying said comparing step to allow output load transients to attenuate prior to said comparing.

11. The method of claim 8 further comprising:

deactivating ones of said plurality of transistors that are associated with said deactivated one or more of said plurality of transistors in a phase of said multiphase circuit.

12. The method of claim 8 further comprising:

latching said deactivated one or more transistors in a deactivated state.

13. A system for preventing catastrophic failure in a multiphase circuit comprising:

a sensor for determining a series resistance of a plurality of transistors;

a resistance monitor for comparing said series resistance to a threshold resistance value; and

a switch for deactivating ones of said plurality of transistors when said series resistance exceeds said threshold resistance value.

14. The system of claim 13 wherein said sensor comprises:

a voltage detector connected across each one of said plurality of transistors to detect a voltage drop across said each one.

15. The system of claim 13 wherein each phase of said multiphase circuit comprises one or more related ones of said plurality of transistors.

16. The system of claim 15 wherein switch deactivates said one or more related ones of said plurality of transistors.

17. The system of claim 13 further comprising:

a latch circuit for maintaining said deactivated ones of said plurality of transistors in a deactivated state.

18. A system for monitoring a status of a plurality of transistors in a multiphase circuit comprising:

means for evaluating a voltage drop across said plurality of transistors;

means for comparing said measured voltage drop against a previously evaluated voltage drop;

means for turning off one or more of said plurality of transistors when said measured voltage drop varies from said previously evaluated voltage drop by predefined value.

19. The system of claim 18 further comprising:

means for holding said evaluated voltage drop for comparison against new evaluated voltage drops.

20. The system of claim 18 further comprising:

means for suspending said means for comparing to allow output load transients to attenuate.

21. The system of claim 18 further comprising:

means for turning off ones of said plurality of transistors that are associated with said turned off one or more of said plurality of transistors in a phase of said multiphase circuit.