Protection circuits for a DC-to-DC converter

• US 20050276081A1
• Filed: 06/14/2004
• Published: 12/15/2005
• Est. Priority Date: 06/14/2004
• Status: Active Grant

• Current Assignee: HP Inc.
• Original Assignee: HP Inc.
• Inventors: Domingo, Reynaldo P., Bemat, Mohamed Amin, Nguyen, Hai N.
• Granted Patent: US 7,053,593 B2
• Time in Patent Office: Days
• US Class Current: 363/65
• CPC Class Codes: H02H 7/1213 for DC-DC converters
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel

Abstract

A DC-to-DC converter comprises a first power module, at least a second power module coupled to the first power module, and a protection circuit coupled to the first and second power modules. The protection circuit causes a system power good signal to be at a state indicative of a power problem when the protection circuit detects that a switching node of one of the power modules has ceased switching.

Claims

1. A DC-to-DC converter, comprising:

a first power module;

at least a second power module coupled to the first power module;

a protection circuit coupled to the first and second power modules;

wherein each power module comprises a controller and first and second power transistors that reciprocally turn on an off, wherein the second power transistor coupled between a switching node and ground in each power module, and wherein the protection circuit forces at least one of the second power transistors to be on during at least a portion of time while an input voltage to the DC-to-DC converter is below a threshold.

2. The converter of claim 1 wherein, once an input voltage reaches a threshold value, the protection circuit releases the at least one second power transistor from being forced on.

3. The converter of claim 1 wherein the protection circuit forces the at least one second power transistor to be on at least until over-voltage protection circuitry in the controller in each module is operational.

4. The converter of claim 1 further comprising a gate driver in each in power module, each gate driver coupled to the controller and the pair of power transistors in the respective power module and to the protection circuit, and the protection circuit forces the input of the gate driver to logic low level to force the second power transistor in each power module to be on while the input voltage is below the threshold.

5. The converter of claim 1 further comprising a second protection circuit coupled to the first and to the second power modules, the second protection circuit causes a system power good signal to be at a state indicative of a power problem when the second protection circuit detects that a switching node of one of the power modules has ceased switching.

6. The converter of claim 1 wherein the protection circuit forces at least one of the second power transistors to be on during at least a portion of time while the input voltage is rising, yet below the threshold, during an initialization.

7. A DC-to-DC converter, comprising:

a first power module;

at least a second power module coupled to the first power module;

a protection circuit coupled to the first and second power modules;

wherein each power module comprises a switching node formed between a pair of power transistors, and wherein the protection circuit causes a system power good signal to be at a state indicative of a power problem when the protection circuit detects that a switching node of one of the power modules has ceased switching.

8. The converter of claim 7 wherein the protection circuit comprises an averaging circuit that produces a voltage indicative of an average voltage of a switching waveform in one of the power modules, said voltage used to control a transistor that causes the system power good signal to be controlled to indicate the presence or absence of a power problem.

9. The converter of claim 7 wherein the first power module controls the system power good signal depending on whether the first module is operational, and the protection circuit causes the system power good signal to be at a state indicative of a power problem if the second module is non-operational.

10. The converter of claim 7 further comprising a second protection circuit that forces an output voltage of the converter to be low during at least a portion of time while the DC-to-DC converter is powering up.

11. The converter of claim 10 wherein the second protection circuit forces the output voltage to be low at least until over-voltage protection circuitry in each module is operational.

12. A system, comprising:

a load; and

a DC-to-DC converter coupled to said load, said converter comprising at least a first power module, a second power module, and a protection circuit coupled to the first and second power modules, wherein the protection circuit forces an output voltage of the DC-to-DC converter to be a predetermined low level during at least a portion of time while an input voltage to the DC-to-DC converter is below a threshold.

13. The system of claim 12 wherein the DC-to-DC converter forces the output voltage to the predetermined low level at least until over-voltage protection circuitry in DC-to-DC converter is operational

14. The system of claim 12 wherein the DC-to-DC converter comprises first and second power modules and a protection circuit coupled to the first and second power modules, and wherein the first power module controls a system power good signal to the load depending on whether the first module is operational, and the protection circuit also controls the system power good signal depending on whether the second module is operational.

15. A system, comprising:

a load; and

a DC-to-DC converter coupled to said load, said converter comprising at least first and second power modules and a protection circuit coupled to the first and second power modules, wherein the protection circuit causes a system power good signal to be at a state indicative of a power problem when the protection circuit detects that a switching node of one of the power modules has ceased switching.

16. The system of claim 15 wherein the converter comprises a second protection circuit that forces an output voltage of the DC-to-DC converter to be low during at least a portion of initialization of the DC-to-DC converter.

17. The system of claim 15 wherein the load comprises a microprocessor.

18. A DC-to-DC converter, comprising:

first means for providing power and, once an input voltage has reached a threshold level, for providing over-voltage protection;

at least a second means for providing power and, once the input voltage has reached the threshold level, for providing over-voltage protection; and

means for forcing an output voltage of the first and second means for providing power to be low while the input voltage is below a threshold until the first and second means provide over-voltage protection.

19. The DC-to-DC converter of claim 18 further comprising means for monitoring an average voltage level of a switching waveform in the second means for providing power and for controlling a system power good signal based on said average voltage level.

20. A DC-to-DC converter, comprising:

first means for providing power and for controlling a system power good signal;

at least a second means for generating a switching waveform and for providing power; and

means for receiving the switching waveform from the second means, for filtering the received switching waveform, and for controlling the system power good signal based on the filtered switching waveform.

21. The converter of claim 20 further comprising means for forcing an output voltage of the first and second means for providing power to be low during at least a portion of an initialization of the DC-to-DC converter.

22. A method, comprising:

converting an input DC voltage to an output DC voltage by a plurality of voltage regulator modules;

after the input DC voltage has reached a threshold level, providing over-voltage protection in said voltage regulator modules;

forcing the output DC voltage from the voltage regulator modules to be low during an initialization process at least until the voltage regulator modules provide over-voltage protection.

23. The method of claim 22 further comprising filtering a switching waveform and controlling a system power good signal based on the filtered switching waveform.

24. A method, comprising:

converting an input DC voltage to an output DC voltage by a first voltage regulator module;

controlling a system power good signal by said first voltage regulator module;

generating a switching waveform in at least a second voltage regulator module;

converting the input DC voltage to an output DC voltage by said second voltage regulator module;

receiving the switching waveform from the second voltage regulator module;

filtering the received switching waveform; and

controlling the system power good signal based on the filtered switching waveform.

25. The method of claim 24 wherein controlling the system power good signal based on the filtered switching waveform comprises setting the power good signal to a state indicative of an absence of a power problem if the filtered switching waveform is indicative of an operational second voltage regulator module.

26. The method of claim 24 wherein controlling the system power good signal based on the filtered switching waveform comprises setting the power good signal to a state indicative of a power problem if the filtered switching waveform indicates improper operation of the second voltage regulator.