Off-line converter with digital control

• US 6,876,181 B1
• Filed: 03/18/2004
• Issued: 04/05/2005
• Est. Priority Date: 02/27/1998
• Status: Expired due to Fees

• Current Assignee: Power Integrations Incorporated
• Original Assignee: Power Integrations Incorporated
• Inventors: Balakrishnan, Balu, Lund, Leif O., Djenguerian, Alex B.
• Primary Examiner(s): HAN, YOUNGHUIE JESSICA
• Application Number:
  US10/805,661
• Time in Patent Office: 383 Days
• Field of Search: 323/282, 323/284, 323/285, 323/283, 363/16, 363/18, 363/19, 363/20, 363/97, 363/131
• US Class Current: 323/285
• CPC Class Codes: H02M 3/157 with digital control
• CPC Class Codes: H02M 3/335 using semiconductor devices only
• 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: H02M 3/33515 with digital control
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop

Abstract

A DC to DC converter comprising an energy storage element comprising an energy storage element input and energy storage element output, the energy storage element input coupled to receive a first power level and the energy storage element output providing a second power level. The converter also comprises a feedback circuit comprising a feedback input and a feedback output, the feedback input coupled to the energy storage element output. The converter further comprises a regulator circuit comprising a regulator circuit feedback input and a regulator circuit output, the regulator circuit feedback input coupled to the feedback output and the regulator circuit output coupled to the energy storage element input, the regulator circuit regulating the input of the first power level to the energy storage element input. When a signal at the regulator circuit feedback input is above a threshold level the regulator circuit ceasing operation and when the signal at the regulator circuit feedback input is below the threshold level the regulator circuit is enabled.

Claims

1. A method, comprising:

receiving a feedback signal having a first feedback state that represents that an output level of a power converter is above a threshold level and a second feedback state that represents the output level of the power converter is below the threshold level;

cycling an oscillating signal having a first frequency under a first set of conditions and a second frequency under a second set of conditions; and

operating a switch having including a first terminal, a second terminal and a control terminal to couple or decouple the first terminal and the second terminal in response to a control signal received at the control terminal to regulate the output level of the power converter, the control signal being responsive to the oscillating signal and to a change between the first and second feedback states.

2. The method of claim 1 further comprising not cycling the oscillating signal under a third set of conditions.

3. The method of claim 1 wherein one of the first and second frequencies is substantially zero.

4. The method of claim 1 wherein the first set of conditions includes the feedback signal having the second feedback state and the switch being switched on.

5. The method of claim 1 wherein the second set of conditions includes the feedback signal having the first feedback state and the switch being switched off.

6. The method of claim 1 further comprising charging a capacitor coupled to a bypass output with a current source coupled between the bypass output and the switch.

7. The method of claim 1 further comprising:

setting a latch providing the control signal in response to the feed back signal; and

resetting the latch in response to the oscillating signal.