Multi-dimensional pulse width modulation control

1. An apparatus comprising:

a controller operative to:

monitor an error voltage indicating a difference between an output voltage and a setpoint voltage;

based on the monitored error voltage, generate modulation adjustment signals including a frequency adjustment signal and an ON-time adjustment signal; and

modulate a pulse width modulation signal of a first power supply phase in accordance with both the frequency adjustment signal and the ON-time adjustment signal;

wherein the controller is further operative to: i) generate an ON-time setting from the ON-time adjustment signal; ii) generate a switching frequency setting from the frequency adjustment signal; and iii) modulate the pulse width modulation signal via the ON-time setting and the switching frequency setting.

2. The apparatus as in claim 1 , wherein the controller is further operative to generate the modulation adjustment signals based on a magnitude of the error voltage.

3. The apparatus as in claim 1 , wherein the controller is further operative to generate the modulation adjustment signals based on a frequency of the error voltage.

4. The apparatus as in claim 1 , wherein the controller is further operative to concurrently: i) adjust a frequency of the pulse width modulation signal based on the frequency adjustment signal, and ii) adjust an ON-time of the pulse width modulation signal based on the ON-time adjustment signal.

5. The apparatus as in claim 1 , wherein the modulation adjustment signals are first modulation adjustment signals;

wherein the frequency adjustment signal is a first frequency adjustment signal associated with the first power supply phase;

wherein the ON-time adjustment signal is a first ON-time adjustment signal associated with the first power supply phase;

wherein the controller is further operative to:

based on the monitored error voltage, generate second modulation adjustment signals including a second frequency adjustment signal and a second ON-time adjustment signal; and

modulate a second pulse width modulation signal of a second power supply phase in accordance with the second ON-time adjustment signal.

6. The apparatus as in claim 1 , wherein the controller includes:

an accumulator operative to monitor passage of a period of the switching frequency signal; and

restart the pulse width modulation signal in response to comparing an output of the accumulator to a threshold signal.

7. A system comprising:

a circuit substrate;

the claim 1 coupled to the circuit substrate; and

wherein the controller controls the first power supply phase.

8. A method comprising:

receiving a circuit substrate; and

coupling the apparatus of claim 1 to the circuit substrate.

9. The method as in claim 1 , wherein the controller includes:

via an accumulator, monitoring passage of a period of the switching frequency signal; and

restarting the pulse width modulation signal in response to detecting that an output of the comparator equals a threshold signal.

10. The apparatus as in claim 1 , wherein the controller includes a first gain transfer function and a second gain transfer function;

wherein the first gain transfer function is operative to convert the monitored error voltage into the frequency adjustment signal; and

wherein the second gain transfer function is operative to convert the monitored error voltage into the ON-time adjustment signal.

11. The apparatus as in claim 1 , wherein the controller includes a PID controller operative to produce a current target signal, the controller further operative to:

convert the current target signal into the modulation adjustment signals.

12. The apparatus as in claim 1 , wherein the controller is further operative to:

map the error voltage into the modulation adjustment signals via a mapping function.

13. The apparatus as in claim 1 , wherein the controller includes a PID controller operative to produce a target duty cycle, the controller further operative to:

convert the target duty cycle into the modulation adjustment signals.

14. An apparatus comprising:

a controller operative to:

monitor an error voltage indicating a difference between an output voltage and a setpoint voltage;

based on the monitored error voltage, generate modulation adjustment signals including a frequency adjustment signal and an ON-time adjustment signal; and

modulate a pulse width modulation signal of a first power supply phase in accordance with both the frequency adjustment signal and the ON-time adjustment signal;

wherein the controller includes a first gain transfer function and a second gain transfer function;

wherein the first gain transfer function is operative to convert the monitored error voltage into the frequency adjustment signal; and

wherein the second gain transfer function is operative to convert the monitored error voltage into the ON-time adjustment signal.

15. The apparatus as in claim 14 , wherein the first gain transfer function and the second gain transfer function are correlated to each other to generate the pulse width modulation signal at different desired effective duty cycles over a range of different error voltages.

16. An apparatus comprising:

a controller operative to:

monitor an error voltage indicating a difference between an output voltage and a setpoint voltage;

based on the monitored error voltage, generate modulation adjustment signals including a frequency adjustment signal and an ON-time adjustment signal; and

modulate a pulse width modulation signal of a first power supply phase in accordance with both the frequency adjustment signal and the ON-time adjustment signal;

wherein the controller is further operative to:

i) generate a nominal frequency value to which the frequency adjustment signal is applied to produce a frequency setting at which to generate the pulse width modulation signal; and

ii) generate a nominal ON time value to which the ON-time adjustment signal is applied to produce an ON-time setting of the pulse width modulation signal.

17. An apparatus comprising:

a controller operative to:

monitor an error voltage indicating a difference between an output voltage and a setpoint voltage;

based on the monitored error voltage, generate modulation adjustment signals including a frequency adjustment signal and an ON-time adjustment signal;

modulate a pulse width modulation signal of a first power supply phase in accordance with both the frequency adjustment signal and the ON-time adjustment signal; and

wherein the controller includes a PID controller operative to produce a current target signal, the controller further operative to:

convert the current target signal into the modulation adjustment signals.

18. An apparatus comprising:

a controller operative to:

monitor an error voltage indicating a difference between an output voltage and a setpoint voltage;

based on the monitored error voltage generate modulation adjustment signals including a frequency adjustment signal and an ON-time adjustment signal; and

modulate a pulse width modulation signal of a first power supply phase in accordance with both the frequency adjustment signal and the ON-time adjustment signal;

wherein the controller is further operative to: map the error voltage into the modulation adjustment signals via a mapping function.

19. The apparatus as in claim 18 , wherein the effective duty cycle, as-produced by the mapping function and modulation adjustment signals, relative to the error voltage is linear.

20. The apparatus as in claim 18 , wherein the effective duty cycle, as-produced by the mapping function and modulation adjustment signals, relative to the error voltage is non-linear.

21. A method comprising:

monitoring an error voltage indicating a difference between an output voltage and a setpoint voltage;

based on the monitored error voltage, generating modulation adjustment signals including a frequency adjustment signal and an ON-time adjustment signal;

modulating a pulse width modulation signal of a first power supply phase in accordance with both the frequency adjustment signal and the ON-time adjustment signal;

via a first gain transfer function, converting the monitored error voltage into the frequency adjustment signal; and

via a second gain transfer function, converting the monitored error voltage into the ON-time adjustment signal.

22. The apparatus as in claim 21 further comprising:

generating the modulation adjustment signals based on a magnitude of the error voltage.

23. The method as in claim 21 further comprising:

generating the modulation adjustment signals based on a frequency of the error voltage.

24. The method as in claim 21 , wherein the first gain transfer function and the second gain transfer function are correlated to each other to generate the pulse width modulation signal at desired effective duty cycles over a range of different error voltages.

25. The method as in claim 21 further comprising;

concurrently: i) adjusting a frequency of the pulse width modulation signal based on the frequency adjustment signal, and ii) adjusting an ON-time of the pulse width modulation signal based on the ON-time adjustment signal.

26. The method as in claim 21 further comprising:

generating a nominal frequency value to which the frequency adjustment signal is applied to produce a frequency setting at which to generate the pulse width modulation signal; and

generating a nominal ON time value to which the ON-time adjustment signal is applied to produce an ON-time setting of the pulse width modulation signal.

27. The method as in claim 21 , wherein the modulation adjustment signals are first modulation adjustment signals;

wherein the frequency adjustment signal is a first frequency adjustment signal associated with the first power supply phase;

wherein the ON-time adjustment signal is a first ON-time adjustment signal associated with the first power supply phase;

the method further comprising:

based on the monitored error voltage, generating second modulation adjustment signals including a second frequency adjustment signal and a second ON-time adjustment signal; and

modulating a second pulse width modulation signal of a second power supply phase in accordance with the second ON-time adjustment signal.

28. The method as in claim 21 further comprising:

via a PID controller, producing a current target signal; and

converting the current target signal into the modulation adjustment signals.

29. The method as in claim 21 further comprising:

via mapping function, mapping the error voltage into the modulation adjustment signals.

30. The method as in claim 29 , wherein the effective duty cycle produced by the mapping function and modulation adjustment signals relative to the error voltage is linear.

31. The method as in claim 29 , wherein the effective duty cycle produced by the mapping function and modulation adjustment signals relative to the error voltage is non-linear.

32. The method as in claim 21 further comprising:

generating an ON-time setting from the ON-time adjustment signal;

generating a switching frequency setting from the frequency adjustment signal; and

modulating the pulse width modulation signal via the ON-time setting and the switching frequency setting.

33. An apparatus comprising:

a controller operative to:

monitor an error voltage indicating a difference between an output voltage and a setpoint voltage;

based on the monitored error voltage, generate modulation adjustment signals including a frequency adjustment signal and an ON-time adjustment signal;

modulate a pulse width modulation signal of a first power supply phase in accordance with both the frequency adjustment signal and the ON-time adjustment signal; and

wherein the controller is further operative to i) adjust an ON-time of the pulse width modulation signal based on the ON-time adjustment signal until the ON-time reaches a specified maximum value, and ii) adjust a frequency of the pulse width modulation signal based on the frequency adjustment signal if the ON-time has reached the specified maximum value.

34. An apparatus comprising:

a controller operative to:

monitor an error voltage, indicating a difference between an output voltage and a setpoint voltage,

based on the monitored error voltage, generate modulation adjustment signals including a frequency adjustment signal and an ON-time adjustment signal; and

modulate a pulse width modulation signal of a first power supply phase in accordance with both the frequency adjustment signal and the ON-time adjustment signal;

wherein the controller includes a PID controller operative to produce a target duty cycle, the controller further operative to: convert the target duty cycle into the modulation adjustment signals.