Power supply output monitor

• US 20060263031A1
• Filed: 03/01/2006
• Published: 11/23/2006
• Est. Priority Date: 05/23/2005
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Inventors: Schiff, Tod F., Goldhammer, Rodney J., Reizik, Gabor T.
• Granted Patent: US 7,466,894 B2
• Time in Patent Office: Days
• US Class Current: 385/147
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel

Abstract

A power supply monitoring system generates a monitor signal having information on more than one aspect of the power supply output. In one example embodiment, the monitor signal may be implemented as a square wave in which the duty cycle is proportional to output current, the peak amplitude is proportional to output voltage, and the average value is equal to output power.

Claims

1. A power supply monitoring system comprising circuitry to generate a monitor signal having information on more than one aspect of the power supply output.

2. The system of claim 1 where the monitor signal includes current and voltage information for the power supply output.

3. The system of claim 2 where:

a first aspect of the monitor signal includes the voltage information; and

a second aspect of the monitor signal includes the current information.

4. The system of claim 2 where the monitor signal further includes power information for the power supply output.

5. The system of claim 4 where:

a first aspect of the monitor signal includes the voltage information;

a second aspect of the monitor signal includes the current information; and

the first and second aspects may be combined to provide the power information.

6. The system of claim 5 where the monitor signal has a pulse waveform.

7. The system of claim 6 where:

the amplitude of a pulse represents the voltage information;

the duty cycle of the monitor signal represents the current information; and

the amplitude times the duty cycle represents the power information.

8. The system of claim 6 where:

the amplitude of a pulse represents the current information;

the duration of a pulse represents the voltage information; and

the amplitude times the pulse duration duty cycle represents the power information.

9. The system of claim 1 where the monitor signal may be reconfigured by a user.

10. The system of claim 1 where the circuitry includes an output driver to establish an amplitude of the monitor signal in response to an aspect of the power supply output.

11. The system of claim 10 where the output driver includes a pair of transistors arranged to switch the monitor signal between a first voltage and a second voltage.

12. The system of claim 11 further including a filter circuit coupled to the output driver.

13. The system of claim 1 where the circuitry includes a pulse generator arranged to create pulses in the monitor signal in response to an aspect of the power supply output.

14. The system of claim 13 where the length of the pulses is related to the aspect of the power supply output.

15. The system of claim 13 where the pulse generator includes a comparator having a ramp signal applied to a first input of the comparator.

16. The system of claim 15 where a signal having information on the aspect of the power supply output is applied to a second input of the comparator.

17. The system of claim 15 where a signal having information on the aspect of the power supply output is combined with the ramp signal.

18. The system of claim 15 where a signal having information on the aspect of the power supply output is applied differentially to the first input and a second input of the comparator.

19. The system of claim 1 where the power supply is a switching power supply.

20. A method of monitoring a power supply output comprising generating a monitor signal having information on more than one aspect of the power supply output.

21. The method of claim 20 where the monitor signal has an amplitude related to an aspect of the power supply output.

22. The method of claim 20 where the monitor signal has a time aspect related to an aspect of the power supply output.

23. The method of claim 22 where the time aspect includes a pulse duration, a signal period, or a duty cycle.

24. The method of claim 20 where the monitor signal includes an oscillating signal having an amplitude related to a first aspect of the power supply output and a time aspect related to a second aspect of the power supply output.

25. The method of claim 24 further including recovering information on a third aspect of the power supply output from the information on the first and second aspects of the power supply output.

26. The method of claim 25 where recovering information on the third aspect includes filtering the oscillating signal.

27. The method of claim 25 where recovering information on the third aspect includes multiplying the amplitude and the time aspect.

28. The method of claim 20 where the power supply is a switching power supply.

29. A power supply monitoring system comprising:

first means for modulating a square wave signal with information on a first aspect of the power supply output; and

second means for modulating the square wave signal with information on a second aspect of the power supply output.

30. The system of claim 29 where the first means for modulating comprises an output driver having means for switching the square wave signal between two voltages in response to the first aspect of the power supply output.

31. The system of claim 29 where the second means for modulating comprises:

means for providing a ramp signal; and

means for comparing the ramp signal to a second signal.

32. The system of claim 31 where the second means for modulating further comprises means for modulating the ramp signal with information on the second aspect of the power supply output.

33. The system of claim 31 where the second means for modulating further comprises means for modulating the second signal with information on the second aspect of the power supply output.

34. The system of claim 31 where the power supply is a switching power supply.