POWER FACTOR CORRECTION CONTROLLER WITH FEEDBACK REDUCTION

• US 20080272745A1
• Filed: 12/31/2007
• Published: 11/06/2008
• Est. Priority Date: 05/02/2007
• Status: Active Grant

• Current Assignee: Cirrus Logic Incorporated
• Original Assignee: Cirrus Logic Incorporated
• Inventors: Melanson, John L.
• Granted Patent: US 8,040,703 B2
• Time in Patent Office: Days
• US Class Current: 323/205
• 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 feedback loop having a power factor correction (PFC) and output voltage controller and a switching power converter. The switching power converter includes an inductor to supply charge to an output capacitor and a switch to control inductor current ramp-up times. The PFC and output voltage controller provides a control signal to the switch to control PFC and regulate output voltage of the switching power converter. During a single period of the control signal, the PFC and output voltage controller obtains the line input voltage and output voltage of the switching power converter using a single feedback signal received from the switching power converter.

Claims

1. A power factor correction (PFC) controller to control power factor correction and regulate output voltage of a switching power converter, wherein the switching power converter includes an inductor to couple to a line input voltage node and a switch coupled to the inductor, the PFC controller comprising:

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

wherein the PFC controller is configured to;

(a) determine at least one of;

(i) a line input voltage and (ii) an output voltage of the switching power converter from the feedback signal;

(b) provide a control signal to the switch such that during each period of the switch the switching power converter responds to the control signal and current ramps-up in the inductor for a first time interval when the switch conducts and ramps-down in the inductor for an inductor flyback time interval when the switch is nonconductive;

(c1) wherein, if the line input voltage is determined in (a), the PFC controller is further configured to determine the output voltage of the switching power converter using the line input voltage, the inductor flyback time interval, and the first time interval; and

(c2) wherein, if the output voltage of the switching power converter is determined in (a), the PFC controller is further configured to determine the line input voltage using the output voltage, the inductor flyback time interval, and the first time interval.

2. The PFC controller of claim 1 wherein the PFC controller is configured to determine the output voltage of the switching power converter in accordance with:

3. The PFC controller of claim 1 wherein the PFC controller is configured to determine the line input voltage of the switching power converter in accordance with:

4. The PFC controller of claim 1 wherein the PFC controller is configured to determine the inductor flyback time interval.

5. The PFC controller of claim 4 wherein the switch comprises a field effect transistor and the PFC and output voltage controller is configured to sense voltage transients on a gate of the switch to determine the inductor flyback time interval T₂.

6. The PFC controller of claim 1 wherein, during operation of the PFC controller and the switching power converter, the sensor senses the line input voltage across the inductor.

7. The PFC controller of claim 6 wherein the sensor further comprises a secondary winding magnetically coupled to the inductor to sense the voltage across the inductor.

8. The PFC controller of claim 1 wherein the PFC controller is further configured to determine the output voltage of the switching power converter using the line input voltage, the inductor flyback time interval, and the first time interval and determine the line input voltage using the output voltage, the inductor flyback time interval, and the first time interval.

9. The PFC controller of claim 1 wherein the PFC controller comprises an integrated circuit having a number of contacts to provide external connections, wherein the pins of the PFC controller include a contact for only one member of a group consisting of:

(i) the line input voltage and (ii) the output voltage of the switching power converter from the feedback signal.

10. A power factor correction (PFC) controller to control power factor correction and regulate output voltage of a switching power converter, wherein the switching power converter includes an inductor to couple to a line input voltage node and a switch coupled to the inductor, the PFC controller comprising:

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

wherein the PFC controller is configured to;

determine a line input voltage;

provide a control signal to the switch such that during each period of the switch the switching power converter responds to the control signal and current ramps-up in the inductor for a first time interval when the switch conducts and ramps-down in the inductor for an inductor flyback time interval when the switch is nonconductive; and

determine the output voltage of the switching power converter using the line input voltage, the inductor flyback time interval, and the first time interval.

11. A power factor correction (PFC) controller to control power factor correction and regulate output voltage of a switching power converter, wherein the switching power converter includes an inductor to couple to a line input voltage node and a switch coupled to the inductor, the PFC controller comprising:

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

wherein the PFC controller is configured to;

determine an output voltage of the switching power converter from the feedback signal;

provide a control signal to the switch such that during each period of the switch the switching power converter responds to the control signal and current ramps-up in the inductor for a first time interval when the switch conducts and ramps-down in the inductor for an inductor flyback time interval when the switch is nonconductive; and

determine the line input voltage using the output voltage, the inductor flyback time interval, and the first time interval.

12. A method of controlling power factor correction and regulating output voltage of a switching power converter, wherein the switching power converter includes an inductor to couple to a line input voltage node and a switch coupled to the inductor, the method comprising:

receiving a feedback signal from the switching power converter;

(a) determining at least one of;

(i) a line input voltage and (ii) an output voltage of the switching power converter from the feedback signal;

(b) providing a control signal to the switch such that during each period of the switch the switching power converter responds to the control signal and current ramps-up in the inductor for a first time interval when the switch conducts and ramps-down in the inductor for an inductor flyback time interval when the switch is nonconductive;

(c1) wherein, if the line input voltage is determined in (a), determining the output voltage of the switching power converter using the line input voltage, the inductor flyback time interval, and the first time interval; and

(c2) wherein, if the output voltage of the switching power converter is determined in (a), determining the line input voltage using the output voltage, the inductor flyback time interval, and the first time interval.

13. The method of claim 12 further comprising:

determining the output voltage of the switching power converter in accordance with;

14. The method of claim 12 further comprising:

determining the output voltage of the switching power converter in accordance with;

15. The method of claim 12 further comprising:

determining the inductor flyback time interval.

16. The method of claim 15 wherein the switch comprises a field effect transistor, the method further comprising:

sensing voltage transients on a gate of the switch to determine the inductor flyback time interval T₂.

17. The method of claim 12 further comprising:

generating the feedback signal via a secondary winding magnetically coupled to the inductor.

18. The method of claim 12 further comprising:

sensing the line input voltage across the inductor.

19. The method of claim 18 wherein sensing the line input voltage across the inductor comprises:

inducing a current in a secondary winding from current in the inductor;

sensing the induced current;

converting the sensed induced current into a voltage corresponding to the line input voltage; and

sensing the voltage corresponding to the line input voltage.

20. The method of claim 12 wherein the switching power converter further includes a capacitor coupled to the inductor, the switch, and an output voltage node, the method further comprising:

sensing the switching power converter output voltage across the capacitor.

21. A method of controlling power factor correction and regulating output voltage of a switching power converter, wherein the switching power converter includes an inductor to couple to a line input voltage node and a switch coupled to the inductor, the method comprising:

receiving a feedback signal from the switching power converter;

determining a line input voltage;

providing a control signal to the switch such that during each period of the switch the switching power converter responds to the control signal and current ramps-up in the inductor for a first time interval when the switch conducts and ramps-down in the inductor for an inductor flyback time interval when the switch is nonconductive; and

determining an output voltage of the switching power converter using the line input voltage, the inductor flyback time interval, and the first time interval.

22. A method of controlling power factor correction and regulating output voltage of a switching power converter, wherein the switching power converter includes an inductor to couple to a line input voltage node and a switch coupled to the inductor, the method comprising:

receiving a feedback signal from the switching power converter;

determining an output voltage of the switching power converter from the feedback signal;

providing a control signal to the switch such that during each period of the switch the switching power converter responds to the control signal and current ramps-up in the inductor for a first time interval when the switch conducts and ramps-down in the inductor for an inductor flyback time interval when the switch is nonconductive; and

determining a line input voltage using the output voltage, the inductor flyback time interval, and the first time interval.