Power supply circuit with a control terminal for different functional modes of operation

• US 8,310,845 B2
• Filed: 02/10/2010
• Issued: 11/13/2012
• Est. Priority Date: 02/10/2010
• Status: Expired due to Fees

• Current Assignee: Power Integrations Incorporated
• Original Assignee: Power Integrations Incorporated
• Inventors: Gaknoki, Yury, Pastore, Tiziano, Mao, Mingming, Matthews, David Michael Hugh
• Primary Examiner(s): Berhane, Adolf
• Assistant Examiner(s): PHAM, EMILY P
• Application Number:
  US12/658,479
• Publication Number:
  US 20110194315A1
• Time in Patent Office: 1,007 Days
• Field of Search: 323/284, 363/21.12, 363/21.17
• US Class Current: 363/21.12
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• 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
• CPC Class Codes: H05B 45/385 using flyback topology
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A method of operation for flyback power converter includes operating a controller of the flyback power converter in a regulation mode when a control signal is below a first threshold. The control signal is provided as an input to a terminal of the flyback power converter. When the control signal is below a second threshold and above the first threshold, the controller is operated in a limiting mode. The controller is operated in an external command mode when the control signal is below a third threshold and above the second threshold. Lastly, when the control signal is above the third threshold, the controller is operated in a protection mode.

Claims

1. A method of operation for a flyback power converter, comprising:

operating a controller of the flyback power converter in a regulation mode when a control signal is below a first threshold;

operating the controller in a limiting mode when the control signal is below a second threshold and above the first threshold;

operating the controller in an external command mode when the control signal is below a third threshold and above the second threshold; and

operating the controller in a protection mode when the control signal is above the third threshold,

wherein the control signal is provided as an input to a control terminal coupled to the controller.

2. The method of claim 1 wherein the first threshold is approximately 550 mV.

3. The method of claim 1 wherein the second threshold is approximately 1 V.

4. The method of claim 1 wherein the third threshold is approximately 2V.

5. The method of claim 1 further comprising, while operating in the regulation mode, switching a power switch by the controller in response to an output current.

6. The method of claim 5 further comprising, while operating in the regulation mode, adjusting a duty cycle of the power switch by the controller every half line cycle.

7. The method of claim 5 further comprising, while operating in the regulation mode, adjusting a switching frequency of the power switch in response to sensing the output current.

8. The method of claim 1 further comprising, while operating in the limiting mode, switching a power switch in response to an output current.

9. A method of operation for a flyback power converter, comprising:

operating a controller of the flyback power converter in a regulation mode when a control signal is below a first threshold;

operating the controller in a limiting mode when the control signal is below a second threshold and above the first threshold;

operating the controller in an external command mode when the control signal is below a third threshold and above the second threshold; and

operating the controller in a protection mode when the control signal is above the third threshold,

wherein the control signal is provided as an input to a control terminal coupled to the controller; and

while operating in the limiting mode, disabling the power switch during a switching cycle when the control terminal exceeds the second threshold.

10. A power converter comprising:

a terminal to receive an external command signal;

a power switch;

a controller coupled to drive the power switch in such a manner as to produce a pulsating current having a frequency;

energy transfer means for transferring energy from an input side of the power converter to a load to be coupled to an output of the power converter;

feedback means for sensing an output current delivered to the load, and generating a control signal received by a control terminal of the controller, the feedback means also being coupled to the control terminal such that when the control signal is below a first threshold, the controller operates in a first mode in which the controller controls the power switch in a closed feedback loop such that the substantially constant output current is regulated at a certain value, when the control signal is above the first threshold and below a second voltage threshold, the controller operates in a second mode in which the controller controls the switch so as to limit the substantially constant output current below a maximum value, when the external command input is above the second voltage threshold and below a third voltage threshold, the controller operates in a third mode in which the controller controls the power switch in response to the external command signal, and when the control signal is above the third voltage threshold the controller operates in a fourth mode in which the controller turns the power switch off and the power converter enters a shutdown mode.