Method and apparatus for high-side input winding regulation

• US 8,724,344 B2
• Filed: 06/01/2012
• Issued: 05/13/2014
• Est. Priority Date: 10/14/2009
• Status: Expired due to Fees

• Current Assignee: Power Integrations Incorporated
• Original Assignee: Power Integrations Incorporated
• Inventors: Matthews, David Michael Hugh
• Primary Examiner(s): PATEL, RAJNIKANT B
• Application Number:
  US13/486,287
• Publication Number:
  US 20120243266A1
• Time in Patent Office: 711 Days
• Field of Search: 363 16- 20, 363/21.04, 363/21.07, 363/21.12, 363/21.13, 363/21.16, 363/49, 363/72, 363/80, 363/89, 363/131, 320/103, 320/107, 320/114, 320/127, 320/133, 320/145, 320/160, 320/158, 323/222, 323282-285
• US Class Current: 363/16
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence

Abstract

A controller for use in a power converter includes a control circuit coupled to control switching of a power switch coupled between a positive input supply rail of the power converter and an energy transfer element input of the power converter. A sampling circuit is coupled to the control circuit and is coupled to receive a signal across the energy transfer element input during an off time of the power switch to provide a sampled output of the converter. The sampled output of the power converter is disabled from being resampled by the sampling circuit during an on time of the power switch. A switch conduction scheduling circuit is included in the control circuit and is coupled to the sampling circuit such that the control circuit is coupled to switch the power switch in response to the sampled output of the power converter.

Claims

1. A controller for use in a power converter, comprising:

a control circuit coupled to control switching of a power switch coupled between a positive input supply rail of the power converter and an energy transfer element input of the power converter;

a sampling circuit coupled to the control circuit and coupled to receive a signal across the energy transfer element input of the power converter during an off time of the power switch to provide a sampled output of the converter, wherein the sampled output of the power converter is disabled from being resampled by the sampling circuit during an on time of the power switch; and

a switch conduction scheduling circuit included in the control circuit and coupled to the sampling circuit such that the control circuit is coupled to switch the power switch in response to the sampled output of the power converter.

2. The controller of claim 1 wherein the sampling circuit includes a signal comparator coupled to receive the signal across the energy transfer element input of the power converter as a current through a resistor coupled to the input of the energy transfer element input of the power converter.

3. The controller of claim 1 wherein the sampling circuit includes a signal comparator coupled to receive the signal across the energy transfer element input of the power converter as a voltage from a resistor divider coupled across the input of the energy transfer element input of the power converter.

4. The controller of claim 1 wherein the energy transfer element comprises a primary winding of a transformer coupled to the energy transfer element input.

5. The controller of claim 1 wherein the switch conduction scheduling circuit is coupled to disable the power switch from being switched for one or more consecutive clock cycles of the controller in response to the sampled output of the power converter being greater than a threshold value.

6. The controller of claim 1 wherein the switch conduction scheduling circuit is coupled to enable the power switch to be switched during a next clock cycle of the controller in response to the sampled output of the power converter being less than a threshold value.

7. The controller of claim 1 wherein the sampling circuit comprises a latch coupled to latch the signal across the energy transfer element input of the power converter during the off time of the power switch in response to the control circuit.

8. The controller of claim 1 wherein the signal across the energy transfer element input of the power supply during the off time of the power switch is representative of an output voltage of the power supply.

9. The controller of claim 1 wherein the signal across the energy transfer element input of the power supply during an on time of the power switch is representative of an input voltage of the power supply.

10. The controller of claim 9 wherein the sampling circuit is coupled to sample the signal across the energy transfer element input of the power supply during the on time of the power switch to provide a sampled input of the power supply.

11. The controller of claim 1 further comprising a current limit circuit coupled to the power switch and the control circuit, the current limit circuit coupled to limit a current through the power switch.