Method and apparatus for implementing an unregulated dormant mode with an event counter in a power converter

Patent metadata

Field	Value
Publication number	US-10284100-B2
Application number	US-201816054860-A
Country	US
Kind code	B2
Filing date	Aug 3, 2018
Priority date	Feb 5, 2009
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

A power converter includes an energy transfer element coupled between an input and an output of the power converter. A switch is coupled to the energy transfer element and a control circuit. The control circuit includes a drive signal generator to generate a drive signal to control switching of the switch to regulate the output of the power converter. An event detection circuit is coupled to the drive signal generator to indicate if a switching period of one switching cycle of the drive signal exceeds a threshold switching period. An event counter circuit is coupled to the event detection circuit to render dormant the drive signal generator for a period of time determined by a timer circuit if the event detection circuit indicates a period of a switching cycle of the drive signal exceeds the threshold switching period for a threshold consecutive number of switching cycles.

First claim

What is claimed is:

1. A power converter, comprising:
an energy transfer element coupled between an input of the power converter and an output of the power converter;
a switch coupled to the energy transfer element; and
a control circuit coupled to the switch, wherein the control circuit comprises:
a drive signal generator coupled to the switch to generate a drive signal to control switching of the switch to regulate a transfer of energy from the input of the power converter to the output of the power converter;
an event detection circuit coupled to the drive signal generator to indicate if a switching period of one switching cycle of the drive signal exceeds a threshold switching period;
an event counter circuit coupled to the event detection circuit to render dormant the drive signal generator for a period of time determined by a timer circuit if the event detection circuit indicates a period of a switching cycle of the drive signal exceeds the threshold switching period for a threshold consecutive number of switching cycles.

2. The power converter of claim 1 , wherein the drive signal generator is coupled to be unresponsive to the output of the power converter when the drive signal generator is dormant.

3. The power converter of claim 1 , wherein the drive signal generator is coupled to generate the drive signal in a variable frequency control scheme such that a load coupled to the output of the power converter and the switching frequency are linearly related.

4. The power converter of claim 1 , wherein the drive signal generator is coupled to generate the drive signal in an on/off control scheme such that a load coupled to the output of the power converter and the switching frequency are linearly related.

5. The power converter of claim 1 , wherein the control circuit further comprises a terminal coupled to the timer circuit.

6. The power converter of claim 1 , wherein the control circuit further comprises a power up detection circuit coupled to power up the drive signal generator after the drive signal generator has been rendered dormant for the period of time determined by the timer circuit.

7. The power converter of claim 6 , wherein the drive signal generator is coupled to be unresponsive to changes in an energy requirement of the load when the drive signal generator is dormant and responsive to changes in the energy requirement of the load after the period of time determined by the timer circuit has elapsed.

8. The power converter of claim 1 , wherein the control circuit further comprises an oscillator coupled to the event detection circuit.

9. The power converter of claim 8 , wherein the event detection circuit comprises a first counter to count cycles of the oscillator and wherein the event counter circuit comprises a second counter to count a number of times that the event detection circuit counts a threshold number of oscillator cycles.

10. The power converter of claim 9 , wherein the first counter is further coupled to be reset in response to an occurrence of a drive signal pulse prior to the first counter counting the threshold number of oscillator cycles.

11. The power converter of claim 9 , wherein the second counter is further coupled to be reset in response to an occurrence of a drive signal pulse prior to the first counter counting the threshold number of oscillator cycles.

12. A power converter, comprising:
an energy transfer element coupled between an input of the power converter and an output of the power converter;
a switch coupled to the energy transfer element; and
a control circuit coupled to the switch, wherein the control circuit comprises:
a drive signal generator coupled to the switch to generate a drive signal to control switching of the switch to regulate a transfer of energy from the input of the power converter to the output of the power converter,
the drive signal generator capable of generating the drive signal in a burst switching mode responsive to the output of the power converter, wherein the burst switching mode includes a switching state in which switching is enabled and a non-switching state in which switching is disabled;
an event detection circuit coupled to the drive signal generator to indicate if a length of a non-switching state of the burst switching mode is longer than a threshold time period; and
an event counter circuit coupled to the event detection circuit to render dormant the drive signal generator for a period of time determined by a timer circuit if the event detection circuit indicates the length of the non-switching state of the burst switching mode is longer than the threshold time period for a threshold consecutive number of times.

13. The power converter of claim 12 , wherein the drive signal generator is coupled to operate in the burst switching mode in light load and no-load conditions for a load coupled to the output of the power converter.

14. The power converter of claim 12 , wherein the drive signal generator is coupled to be unresponsive to the output of the power converter when the drive signal generator is dormant.

15. The power converter of claim 12 , wherein the control circuit further comprises a terminal coupled to the timer circuit.

16. The power converter of claim 12 , wherein the control circuit further comprises a power up detection circuit coupled to power up the drive signal generator after the drive signal generator has been rendered dormant for the period of time determined by the timer circuit.

17. The power converter of claim 12 , wherein the drive signal generator is coupled to be unresponsive to changes in an energy requirement of the load when the drive signal generator is dormant and responsive to changes in the energy requirement of the load after the period of time determined by the timer circuit has elapsed.

18. A power converter, comprising:
an energy transfer element coupled between an input of the power converter and an output of the power converter;
a switch coupled to the energy transfer element; and
a control circuit coupled to the switch, wherein the control circuit comprises:
a drive signal generator circuit coupled to generate a drive signal having a switching period for each switching cycle comprising an on-time and an off-time, the drive signal to control switching of a power switch to regulate a transfer of energy from the input of the power converter to the output of the power converter,
the drive signal generator circuit capable of generating the drive signal to have a non-constant switching period;
an event detection circuit coupled to indicate if the switching period for a switching cycle exceeds a threshold switching period; and
an event counter circuit coupled to the event detection circuit to place the drive signal generator in a reduced energy consumption state for a period of time determined by a timer circuit if the switching period for the switching cycle exceeds the threshold switching period for a threshold consecutive number of times.

19. The power converter of claim 18 , wherein the threshold consecutive number of times is greater than two.

20. The power converter of claim 18 , wherein the drive signal generator is coupled to be unresponsive to the output of the power converter when the drive signal generator is in the reduced energy consumption state.

21. The power converter of claim 18 , wherein the drive signal generator is coupled to generate the drive signal such that the off time of the drive signal switching period is responsive to the output of the pow

Assignees

• Power Integrations Inc

Inventors

• Djenguerian Alex B
• Lund Leif

Classifications

• H02M2001/0035

  Electricity · mapped topic

• H02M2001/0009

  Electricity · mapped topic

• H02M3/33523 Primary

  with galvanic isolation between input and output of both the power stage and the feedback loop · CPC title

• H02M2001/0032

  Electricity · mapped topic

• Y10T307/406

  Cross-Sectional Technologies · mapped topic