Power factor correction controller with switch node feedback

• US 7,888,922 B2
• Filed: 12/31/2007
• Issued: 02/15/2011
• Est. Priority Date: 05/02/2007
• Status: Active Grant

• Current Assignee: Cirrus Logic Incorporated
• Original Assignee: Cirrus Logic Incorporated
• Inventors: Melanson, John L.
• Primary Examiner(s): Vu; Bao Q
• Application Number:
  US11/967,272
• Publication Number:
  US 20080272746A1
• Time in Patent Office: 1,142 Days
• Field of Search: 323/282, 323/283, 323/284, 323/286, 323/222, 323/223, 323/224
• US Class Current: 323/282
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H03M 3/476 Non-linear conversion systems
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y02P 80/10 Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier

Abstract

A power control system includes a switching power converter and a power factor correction (PFC) and output voltage controller. The PFC and output voltage controller provides a control signal to a switch to control power factor correction and regulate output voltage of the switching power converter. During a single period of the control signal, the PFC and output voltage controller determines the line input voltage, the output voltage, or both using a single feedback signal received from the switching power converter. The feedback signal is received from a switch node located between an inductor and the switch. The PFC and output voltage controller determines either the line input voltage or the output voltage, whichever was not determined from the feedback signal, using a second feedback signal received from either a PFC stage or a driver stage of the switching power converter.

Claims

1. A power factor correction (PFC) controller to control power factor correction of a switching power converter, wherein the switching power converter receives a periodic input signal and the switching power converter includes an inductor coupled to an input node and a switch node, a switch coupled to the switch node, and an output node coupled to a capacitor, the PFC controller comprising:

a first input terminal, coupled to the switch node, to receive a feedback signal from the switch node, wherein the feedback signal from the switch node is distinct from a signal on the output node for a cycle of the input signal; and

wherein the PFC controller is configured to;

determine from the feedback signal at least one of (i) the line input voltage and (ii) an output voltage of the switching power converter;

determine at least one of (i) the line input voltage and (ii) the output voltage of the switching power converter; and

provide a control signal to the switch to control power factor correction of the switching power converter in response to the determined line input voltage and the determined output voltage of the switching power converter.

2. The PFC controller of claim 1 wherein the PFC controller is further configured to determine both the line input voltage and the output voltage of the switching power converter from the feedback signal.

3. The PFC controller of claim 1 wherein the PFC controller is further configured to determine at least one of (i) the line input voltage and (ii) the output voltage of the switching power converter from a feedback signal received from a secondary winding magnetically coupled to the inductor.

4. The PFC controller of claim 1 wherein the PFC controller further comprises a second input terminal coupled to an input node of the switching power converter to receive the line input voltage, and the PFC controller is further configured to determine the output voltage of the switching power converter from the feedback signal.

5. The PFC controller of claim 1 wherein the PFC controller further comprises a second input terminal coupled to an output node of the switching power converter to receive the output voltage of the switching power converter, and the PFC controller is further configured to determine the line input voltage of the switching power converter from the feedback signal.

6. The PFC controller of claim 1 wherein, during operation of the PFC controller and the switching power converter, for each period of a switch control signal the switch conducts for a time interval T1 and the PFC controller is configured to determine the output voltage of the switching power converter from a value of the feedback signal sensed during the time interval T1.

7. The PFC controller of claim 1 wherein, during operation of the PFC controller and the switching power converter, for each period of a switch control signal the switch conducts for a time interval T1 and, after the time interval T1, current in the inductor decreases for a flyback time interval T2, wherein the PFC controller is configured to determine the line input voltage from a value of the feedback signal sensed during the flyback time interval T2.

8. The PFC controller of claim 1 wherein the PFC controller further comprises a second input terminal coupled to the switching power converter and, during operation of the PFC controller and the switching power converter, the second input terminal receives a voltage sensed across the inductor and the PFC controller is configured to determine at least one of (i) the line input voltage and (ii) the output voltage of the switching power converter from the voltage sensed across the inductor.

9. The PFC controller of claim 8 wherein the voltage sensed across the inductor is sensed using a secondary winding magnetically coupled to the inductor.

10. A power factor correction (PFC) controller to control power factor correction and regulate output voltage at an output node of a switching power converter, the PFC controller comprising:

an input to receive a feedback signal from the switching power converter; and

wherein the PFC controller is configured to;

determine a line input voltage and an output voltage of the switching power converter from the feedback signal, wherein during operation of the PFC controller the feedback signal is distinct from a signal on the output node of the switching power converter for a cycle of an input voltage signal supplied to the switching power converter; and

provide a control signal to the switching power converter to control power factor correction and regulate output voltage of the switching power converter in response to the determined line input voltage and the determined output voltage of the switching power converter.

11. A method of controlling power factor correction of a switching power converter, wherein the switching power converter receives a periodic input signal and the switching power converter includes an inductor coupled to an input node and a switch node, a switch coupled to the switch node, and an output node coupled to a capacitor, the method comprising:

receiving a feedback signal from the switch node, wherein the feedback signal from the switch node is distinct from a signal on the output node for a cycle of the input signal;

determining from the feedback signal at least one of (i) the line input voltage and (ii) an output voltage of the switching power converter;

determining at least one of (i) the line input voltage and (ii) the output voltage of the switching power converter; and

providing a control signal to the switch to control power factor correction of the switching power converter in response to the determined line input voltage and the determined output voltage of the switching power converter.

12. The method of claim 11 further comprising:

determining both the line input voltage and the output voltage of the switching power converter from the feedback signal.

13. The method of claim 11 further comprising:

determining at least one of (i) the line input voltage and (ii) the output voltage of the switching power converter from a feedback signal received from a secondary winding magnetically coupled to the inductor.

14. The method of claim 11 further comprising:

determining the output voltage of the switching power converter from the feedback signal.

15. The method of claim 11 further comprising:

determining the line input voltage of the switching power converter from the feedback signal.

16. The method of claim 11 wherein for each period of a switch control signal the switch conducts for a time interval T1, the method further comprising:

determining the output voltage of the switching power converter from a value of the feedback signal sensed during the time interval T1.

17. The method of claim 11 wherein for each period of a switch control signal the switch conducts for a time interval T1 and, after the time interval T1, current in the inductor decreases for a flyback time interval T2, the method further comprising:

determining the line input voltage from a value of the feedback signal sensed during the flyback time interval T2.

18. The method of claim 11 further comprising:

receiving a voltage sensed across the inductor; and

determining at least one of (i) the line input voltage and (ii) the output voltage of the switching power converter from the voltage sensed across the inductor.

19. The method of claim 11 further comprising:

sensing the voltage across the inductor using a secondary winding magnetically coupled to the inductor.

20. An apparatus to control power factor correction of a switching power converter, wherein the switching power converter receives a periodic input signal and the switching power converter includes an inductor coupled to an input node and a switch node, a switch coupled to the switch node, and an output node coupled to a capacitor, the apparatus comprising:

means for receiving a feedback signal from the switch node, wherein the feedback signal from the switch node is distinct from a signal on the output node for a cycle of the input signal;

means for determining from the feedback signal at least one of (i) the line input voltage and (ii) an output voltage of the switching power converter;

means for determining at least one of (i) the line input voltage and (ii) the output voltage of the switching power converter; and

means for providing a control signal to the switch to control power factor correction of the switching power converter in response to the determined line input voltage and the determined output voltage of the switching power converter.