Off-line converter with digital control

• US 6,297,623 B1
• Filed: 08/02/2000
• Issued: 10/02/2001
• Est. Priority Date: 02/27/1998
• Status: Expired due to Term

• 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:
  US09/630,477
• Time in Patent Office: 426 Days
• Field of Search: 323/282, 323/283, 323/284, 323/285, 323/16, 323/18, 323/19, 323/20, 323/97, 323/131
• US Class Current: 323/283
• 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 DC to DC converter comprising an energy storage element comprising an energy storage element input and an 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 regulator circuit comprising:

a feedback input;

a switch comprising a first terminal, a second terminal and a control terminal, said switch coupling said first and second terminals when a control signal is received at said control terminal;

an oscillator comprising an oscillator output that provides a duty cycle signal comprising a high state and a low state;

said control signal being provided when no feedback signal is provided at said feedback input and said duty cycle signal is in said high state.

2. The regulator circuit of claim 1 wherein said switch comprises a transistor.

3. The regulator circuit of claim 1 further comprising an over current blockregulator comprising an input coupled to first terminal of said switch and an output coupled to said control terminal of said switch.

4. The regulator circuit of claim 3 wherein said over current regulator terminates operation of said switch when a current input at said first terminal of said switch is above a current limit.

5. The regulator circuit of claim 1 wherein said regulator circuit comprises a monolithic device.

6. The regulator circuit of claim 1 further comprising a bypass output, a capacitor coupled to said bypass output and a current source coupled between said first terminal of said switch and said bypass output.

7. The regulator circuit of claim 6 wherein said current source provides current to charge said capacitor when said switch does not couple said first terminal to said second terminal.

8. The regulator circuit of claim 1 wherein a frequency of said duty cycle signal is increased when said feedback signal is received.

9. The regulator circuit of claim 1 wherein said duty cycle signal is not provided when said feedback signal is received.

10. The regulator circuit of claim 9 wherein said duty cycle signal is resumed substantially instantaneously with the removal of said feedback signal.