Primary side control circuit and method for ultra-low idle power operation

• US 7,904,738 B2
• Filed: 07/12/2010
• Issued: 03/08/2011
• Est. Priority Date: 05/29/2008
• Status: Expired due to Fees

• Current Assignee: iGo, Inc.
• Original Assignee: iGo, Inc.
• Inventors: DuBose, Richard G.
• Primary Examiner(s): Patel, Nitin C
• Application Number:
  US12/834,607
• Publication Number:
  US 20100281283A1
• Time in Patent Office: 239 Days
• Field of Search: 713/300, 713/320, 713/323, 323/271, 323/317
• US Class Current: 713/300
• CPC Class Codes: H02M 1/0006 Arrangements for supplying an adequate voltage to the control circuit of converters
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A method and circuit for reducing power consumption during idle mode to ultra-low levels, such as about 1/10^th to 1/1000^th or less of active power is disclosed. An ultra-low idle power supply comprises a primary circuit, a secondary circuit and a control circuit. The control circuit monitors behavior of the primary circuit and determines whether an idle state or no load condition exists, and if so the primary circuit is disengaged. By disengaging the primary circuit, the power consumption of the ultra-low idle power supply is reduced to ultra-low levels.

Claims

1. A power supply comprising:

a control circuit on a primary side of said power supply, wherein said control circuit is configured to monitor at least one of a duty cycle or a switching rate within a primary circuit and to control said primary circuit such that said primary circuit is substantially disabled in response to an idle power mode being detected; and

a standby switch configured to transition said power supply from an ultra-low idle power mode to an active mode or a normal idle mode.

2. The power supply of claim 1, wherein said control circuit monitors said at least one of said duty cycle or said switching rate within said primary circuit to determine whether a power level of said power supply is above or below a predetermined threshold.

3. The power supply of claim 2, wherein said control circuit comprises a logic control unit configured for monitoring said primary circuit and a power control unit configured for control of said primary circuit.

4. The power supply of claim 3, wherein said logic control unit and said power control unit comprise at least one of a combinational logic machine, a state machine or a microprocessor.

5. The power supply of claim 3, wherein said primary circuit comprises a modulator circuit configured for driving at least one of a transformer or a dielectric isolation device.

6. The power supply of claim 5, wherein said logic control unit is configured to monitor a signal of said modulator circuit.

7. The power supply of claim 5, wherein said power control unit is configured to control at least one switch to control said modulator circuit.

8. The power supply of claim 5, wherein said modulator circuit comprises a PWM controller.

9. The power supply of claim 1, wherein said control circuit is configured to monitor and control said primary circuit solely in said primary circuit without a feedback signal from outside said primary circuit.

10. The power supply of claim 1, wherein said standby switch is further configured to transition said power supply to said ultra-low idle power mode from said active mode or said normal idle mode.

11. A circuit configured to facilitate an ultra-low idle power mode in a power supply, said circuit having a primary circuit comprising:

a modulator configured for modulating input power to transfer power from a primary side of a transformer to a secondary side of said transformer; and

a standby switch configured to transition said power supply from said ultra-low idle power mode to an active mode or a normal idle mode;

wherein said primary circuit is in communication with a control circuit on a primary side of said power supply, and wherein said control circuit is configured to monitor at least one of a duty cycle or a switching rate of said modulator and to control said primary circuit such that said primary circuit is substantially disabled in response to said control circuit determining that substantially no load exists.

12. The circuit of claim 11, further comprising:

an input circuit configured for filtering and rectifying the input power; and

an energy storage circuit coupled to said input circuit and further coupled to said modulator.

13. The circuit of claim 11, wherein said control circuit comprises a logic control unit configured for monitoring said modulator and a power control unit configured for control of said circuit.

14. The circuit of claim 11, wherein said modulator comprises a PWM controller.

15. The circuit of claim 13, wherein said logic control unit comprises at least one input coupled to said modulator to monitor said at least one of said duty cycle or said switching rate of said modulator.

16. The circuit of claim 15, wherein said at least one input coupled to said modulator monitors at least one of an output pulse rate directly from a PWM controller within said modulator, an output from an integrator coupled to said PWM controller, or an output from a current-to-voltage converter coupled to said PWM controller.

17. The circuit of claim 13, wherein said circuit comprises at least one switch device coupled between said power control unit and said modulator, whereby said power control unit opens said at least one switch device to disable said modulator.

18. A method for providing ultra-low power operation of a power supply comprising:

monitoring, using a control circuit in communication with a primary circuit on a primary side of said power supply, at least one of a duty cycle or a switching rate of said primary circuit of said power supply and determining if substantially no load condition exists;

substantially disabling, using said control circuit, said primary circuit of said power supply in response to said substantially no load condition being detected; and

transitioning, using a standby switch, said power supply from an ultra-low idle power mode to an active mode or a normal idle mode.

19. The method according to claim 18, said method further comprising re-enabling said power supply after a lapsing of a predetermined time interval.

20. The method of claim 18, wherein said determining if said substantially no load condition exists comprises detecting if at least one of a low duty cycle or a switching rate is present within said primary circuit.