Digital serializer based pulsewidth modulator controller

1. A method performed by a pulsewidth modulation (PWM) controller, the method comprising:

receiving a control input including PWM parameters;

producing inputs to a digital serializer, wherein the inputs result in a digital serializer output that is pulsewidth modulated according to the PWM parameters;

receiving current and voltage sense data to be included in a feedback control input; and

modifying inputs to the digital serializer based upon the feedback control input.

2. The method of claim 1 , wherein the producing inputs to the digital serializer includes producing plurality of digital words to produce the pulsewidth modulated output.

3. The method of claim 1 , wherein the feedback control input includes digitally filtering the pulsewidth modulated output.

4. The method of claim 3 , further comprising receiving digital filter parameters to digitally filter the pulsewidth modulated output.

5. The method of claim 1 , wherein modifying input to the digital serializer includes determining a modified duty cycle of the PWM modulation and selecting an ON time and OFF time of the PWM modulation resulting in a duty cycle nearest to the modified duty cycle.

6. The method of claim 5 , where selecting the ON time and OFF time includes searching a table of ON and OFF times.

7. A method performed by a pulsewidth modulation (PWM) controller including a digital serializer, the method comprising:

receiving a control input including PWM parameters;

determining N and M based upon the PWM parameters, wherein N is the number of ON discreet time periods and M is the number of OFF discreet time periods where M+N discreet time periods correspond to a pulse repetition interval;

producing a plurality of digital serializer input data words corresponding to N ON discreet time periods and M OFF discreet time periods;

applying the plurality of digital serializer input data words to the digital serializer to produce a PWM signal having an initial duty cycle;

altering N and determining a desired duty cycle based on a feedback control input; and

varying the pulse repetition interval to result in a duty cycle close to the desired duty cycle.

8. The method of claim 7 , further comprising:

receiving a feedback control input; and

modifying the plurality of digital serializer inputs to the digital serializer based upon the feedback control input.

9. The method of claim 8 , wherein the feedback control input includes digitally filtering the pulsewidth modulated output.

10. The method of claim 9 , further comprising receiving digital filter parameters to digitally filter the pulsewidth modulated output.

11. The method of claim 8 , wherein modifying the plurality of digital serializer inputs to the digital serializer includes determining a modified duty cycle of the PWM modulation and selecting an ON time and OFF time of the PWM modulation resulting in a duty cycle nearest to the modified duty cycle.

12. The method of claim 11 , where selecting the ON time and OFF time includes searching a table of ON and OFF times.

13. A pulsewidth modulation (PWM) controller comprising:

a digital serializer configured to receive a parallel input data stream and to produce a output serial data stream based upon the input parallel data stream; and

a loop controller including an output connected to the digital serializer and an input configured to receive current and voltage sense data to be included in a feedback control input,

wherein the loop controller is configured to output a parallel input data stream to the digital serializer based upon the feedback control input and wherein the output serial data stream from the digital serializer has desired PWM parameters.

14. The PWM controller of claim 13 , wherein the parallel input data stream includes a plurality of digital words to produce the pulsewidth modulated output.

15. The PWM controller of claim 13 , further comprising a digital filter configured to filter the pulsewidth modulated output.

16. The PWM controller of claim 15 , wherein the digital filter is configured to receive digital filter parameters to digitally filter the pulsewidth modulated output and to provide a feedback signal to the loop controller.

17. The PWM controller of claim 13 wherein the loop controller is configured to determine a modified duty cycle of the PWM modulation and to select an ON time and OFF time of the PWM modulation resulting in a duty cycle nearest to the modified duty cycle.

18. The PWM controller of claim 17 , where selecting the ON time and OFF time includes searching a table of ON and OFF times.