1. A switching mode power supply operative in a normal mode and a measure mode, comprising:
an output stage; and
a controller for driving the output stage to produce an output voltage;
wherein the controller compensates the switching mode power supply with a first compensation factor in the measure mode so as to measure a frequency response of the switching mode power supply for determining a second compensation factor which is used to compensate the switching mode power supply in the normal mode.
2. The switching mode power supply of claim 1, wherein the controller has a feedback pin for receiving either a small signal voltage in the measure mode or a feedback signal derived from the output voltage in the normal mode to regulate the output voltage.
3. The switching mode power supply of claim 2, wherein the controller comprises:
an error amplifier for comparing a signal from the feedback pin with a reference voltage to produce an error signal;
a compensator for compensating the error signal with either the first compensation factor in the measure mode or the second compensation factor in the normal mode, so as to produce a compensated error signal; and
a pulse width modulator for driving the output stage according to the compensated error signal.
4. The switching mode power supply of claim 3, further comprising an analog-to-digital converter for digitizing the error signal.
5. The switching mode power supply of claim 3, wherein the compensator comprises:
a digital filter for filtering the error signal to produce a first signal;
an adder having a first input to receive the first signal and a second input to receive a second signal, so as to combine the first and second signals to produce a third signal; and
a multiplexer for selecting a forth signal to be the second signal in the normal mode and a fifth signal to be the second signal in the measure mode.
6. The switching mode power supply of claim 5, wherein the digital filter comprises a gain circuit for amplifying the error signal, the gain circuit having a first gain in the normal mode and a second gain in the measure mode.
7. The switching mode power supply of claim 2, wherein the controller comprises:
an error amplifier for comparing a signal from the feedback pin with a reference voltage to produce an error signal;
a first compensator for compensating the error signal with the first compensation factor in the measure mode to produce a first signal;
a second compensator for compensating the error signal with the second compensation factor in the normal mode to produce a second signal; and
a pulse width modulator for driving the output stage according to the first signal in the measure mode and the second signal in the normal mode.
8. The switching mode power supply of claim 7, further comprising an analog-to-digital converter for digitizing the error signal.
9. The switching mode power supply of claim 7, wherein the first compensator comprises:
a gain circuit for amplifying the error signal; and
an adder having a first input to receive the amplified error signal and a second input to receive a third signal, so as to combine the amplified error signal and the third signal to produce the first signal.
10. The switching mode power supply of claim 7, further comprising a multiplexer for connecting the first signal to the pulse width modulator in the measure mode and the second signal to the pulse width modulator in the normal mode.
11. The switching mode power supply of claim 1, wherein the controller comprises:
an error amplifier for comparing the output voltage with a reference voltage to produce an error signal;
an AC signal generator for providing a small signal voltage;
a first compensator for compensating the small signal voltage with the first compensation factor in the measure mode to produce a first signal;
a second compensator for compensating the error signal with the second compensation factor in the normal mode to produce a second signal;
a pulse width modulator for driving the output stage according to the first signal or the second signal; and
an analyzer for analyzing the small signal voltage and a third signal related to the error signal in the measure mode, to derive the frequency response for determining the second compensation factor.
12. The switching mode power supply of claim 11, further comprising a fast Fourier transformer for transforming the error signal to the third signal.
13. The switching mode power supply of claim 11, further comprising an analog-to-digital converter for digitizing the error signal.
14. The switching mode power supply of claim 11, further comprising a multiplexer for connecting the first signal to the pulse width modulator in the measure mode and the second signal to the pulse width modulator in the normal mode.
15. The switching mode power supply of claim 11, wherein the first compensator comprises:
a gain circuit for amplifying the small signal voltage; and
an adder having a first input to receive the amplified small signal voltage and a second input to receive a fourth signal, so as to combine the amplified small signal voltage and the fourth signal to produce the first signal.
16. A method for determining a compensation factor for a switching mode power supply operative in a normal mode and a measure mode, comprising the steps of:
switching the switching mode power supply to the measure mode;
providing a small signal voltage;
driving an output stage of the switching mode power supply according to the small signal voltage and a first compensation factor, for producing an output voltage; and
deriving a frequency response of the switching mode power supply from the output voltage for determining a second compensation factor which is used to compensate the switching mode power supply in the normal mode.
17. The method of claim 16, wherein the step of driving an output stage of the switching mode power supply according to the small signal voltage and a first compensation factor comprises the steps of:
comparing the small signal voltage with a reference voltage for producing an error signal;
compensating the error signal with the first compensation factor; and
driving the output stage according to the compensated error signal.
18. The method of claim 17, further comprising the step of digitizing the error signal before the step of compensating the error signal with the first compensation factor.
19. The method of claim 16, wherein the step of driving an output stage of the switching mode power supply according to the small signal voltage and a first compensation factor comprises the step of:
compensating the small signal voltage with the first compensation factor; and
driving the output stage according to the compensated small signal voltage.
20. The method of claim 16, wherein the step of deriving a frequency response of the switching mode power supply from the output voltage for determining a second compensation factor comprises the steps of:
comparing the small signal voltage with a reference voltage for producing an error signal;
fast Fourier transforming the error signal; and
analyzing the transformed error signal and the small signal voltage to derive the frequency response.
21. The method of claim 20, further comprising the step of digitizing the error signal before the step of fast Fourier transforming the error signal.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method comprising:
booting a computer system;
copying contents stored in a portion of a system programmable read-only memory (PROM) responsive to said booting;
storing a duplicate of the contents in a storage unit;
periodically comparing the contents stored in the portion of the system PROM with the duplicate of the contents in the storage unit;
performing a system alert if the contents stored in the portion of the system PROM are different from the contents in the storage unit, wherein performing a system alert includes deactivating of system shutdown commands.
2. The method as recited in claim 1, wherein the contents stored in the portion of the system PROM are static.
3. The method as recited in claim 2, wherein the system PROM includes a static portion and a dynamic portion.
4. The method as recited in claim 1, wherein the system PROM is a serial electrically erasable-programmable ROM (SEEPROM).
5. The method as recited in claim 1, wherein performing a system alert includes invoking an indication on a visual display.
6. The method as recited in claim 1, wherein performing a system alert includes providing an audio indication.
7. The method as recited in claim 1 further comprising writing the duplicate of the contents in the storage unit to the portion of the system PROM responsive to determining the contents stored in the portion of the system PROM are different from the contents in the storage unit.
8. The method as recited in claim 1, wherein the system PROM is mounted upon a system board.
9. The method as recited in claim 8, wherein the system board is a field replaceable unit (FRU).
10. The method as recited in claim 9, wherein the FRU is configured for plug-and-play.
11. A computer system comprising:
a system programmable read-only memory (PROM); and
a storage unit;
wherein the computer system is configured to, responsive to booting:
copy contents stored in a portion of the system PROM;
store a duplicate of the contents in the storage unit;
periodically compare the contents stored in the portion of the system PROM to the duplicate of the contents in the storage unit; and
perform a system alert if the contents stored in the portion of the system PROM are different from the duplicate of the contents in the storage unit, wherein performing a system alert includes deactivating of system shutdown commands.
12. The computer system as recited in claim 11, wherein the system PROM is a serial electrically erasable-programmable ROM (SEEPROM).
13. The computer system as recited in claim 11, wherein performing a system alert includes invoking an indication on a visual display.
14. The computer system as recited in claim 11, wherein performing a system alert includes providing an audio indication.
15. The computer system as recited in claim 11, wherein the system is configured to write the duplicate of the contents in the storage unit to the portion of the system PROM responsive to determining the contents stored in the portion of the system PROM are different from the contents in the storage unit.
16. The computer system as recited in claim 11, wherein the system PROM is mounted upon a system board.
17. The computer system as recited in claim 16, wherein the system board is a field replaceable unit (FRU).
18. The computer system as recited in claim 17, wherein the FRU is configured for plug-and-play.
19. The computer system as recited in claim 18, wherein the FRU is configured for hot-plugging.