System and method for input current shaping in a power converter

1. A method of shaping input current to an AC to DC power converter based upon a reference shape of peak current values, the method comprising:

receiving an input voltage signal to the power converter;

determining a count corresponding to a phase of the input voltage signal;

determining turn-on timings and turn-off timings of a switch in the power converter based upon one or more operation modes, at least one of the operation modes configured to determine the turn-off timings of the switch so as to keep the switch on until a current through the switch reaches the peak current value corresponding to the determined count; and

controlling the switch to be turned on and off based upon the determined turn-on timings and the determined turn-off timings.

2. The method of claim 1 , wherein the peak current value is derived from a table storing a plurality of the peak current values corresponding to the reference shape.

3. The method of claim 1 , wherein the peak current value is generated in real time, based upon the determined count and the reference shape.

4. The method of claim 1 , wherein the power converter is a boost power converter.

5. The method of claim 1 , wherein the power converter is a flyback power converter.

6. An AC to DC power converter, comprising:

a power stage for transferring electrical power received in the form of an AC input voltage from a power source to a load;

a switch in the power stage that electrically couples or decouples the load to or from the power source; and

a switch controller coupled to the switch for shaping input current to the power converter based upon a reference shape of peak current values, wherein the switch controller:

determines a count corresponding to a phase of the input voltage signal;

determines turn-on timings and turn-off timings of the switch based upon one or more operation modes, at least one of the operation modes configured to determine the turn-off timings of the switch so as to keep the switch on until a current through the switch reaches the peak current value corresponding to the determined count; and

controls the switch to be turned on and off based upon the determined turn-on timings and the determined turn-off timings, respectively.

7. The AC to DC power converter of claim 6 , wherein the switch controller derives the peak current value from a table storing a plurality of the peak current values corresponding to the reference shape.

8. The AC to DC power converter of claim 6 , wherein the switch controller generates the peak current value in real time, based upon the determined count and the reference shape.

9. The AC to DC power converter of claim 6 , wherein the power stage is a boost-type power stage.

10. The AC to DC power converter of claim 6 , wherein the power stage is a flyback-type power stage.

11. A controller for shaping an input current to an AC to DC power converter, the power converter including a power stage for transferring electrical power from a power source to a load and a switch in the power stage that is controlled by the controller and electrically couples or decouples the load to or from the power source, the controller comprising:

a current shaper module for determining waveform synthesis parameters based upon an input voltage signal and a reference shape of peak current values, and for determining a count corresponding to a phase of the input voltage signal;

an operation mode selector module receiving the waveform synthesis parameters and the count, and selecting at least one of a plurality of operation modes configured to determine turn-on timings and turn-off timings of the switch, at least one of the operation modes configured to determine the turn-off timings of the switch so as to keep the switch on until a current through the switch equals the peak current value corresponding to the determined count; and

a current waveform synthesizer module determining the turn-on timings and the turn-off timings of the switch based upon the selected operation mode and for controlling the switch in accordance with the determined turn-off timings and the determined turn-on timings of the switch, respectively.

12. The controller of claim 11 , wherein the current waveform synthesizer module derives the peak current value from a table storing a plurality of the peak current values corresponding to the reference shape.

13. The controller of claim 11 , wherein the current waveform synthesizer module generates the peak current value in real time, based upon the determined count and the reference shape.

14. The controller of claim 11 , wherein the power stage is a boost-type power stage.

15. The controller of claim 11 , wherein the power stage is a flyback-type power stage.

16. A controller for shaping an input current to an AC to DC power converter, the power converter including a power stage for transferring electrical power received in a form of input voltage from a power source to a load, and a switch in the power stage that is controlled by the controller and electrically couples or decouples the load to or from the power source, wherein the controller:

determines a count corresponding to a phase of the input voltage signal;

determines turn-on timings and turn-off timings of the switch based upon one or more operation modes, at least one of the operation modes configured to determine the turn-off timings of the switch so as to keep the switch on until a current through the switch reaches the peak current value corresponding to the determined count; and

controls the switch to be turned on and off based upon the determined turn-on timings and the determined turn-off timings, respectively.