Circuit and associated method for reducing power consumption in a power transformer

• US 7,852,645 B2
• Filed: 12/12/2007
• Issued: 12/14/2010
• Est. Priority Date: 12/12/2007
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Baumgartner, Richard, Lum, Richard, Fouquet, Julie
• Primary Examiner(s): Sterrett; Jeffrey L
• Assistant Examiner(s): Finch, III; Fred E
• Application Number:
  US11/954,498
• Publication Number:
  US 20090154206A1
• Time in Patent Office: 1,098 Days
• Field of Search: 361/18, 363/53, 363/84, 363/89, 363/125, 363/127, 363/81, 307/39, 323/284
• US Class Current: 363/81
• CPC Class Codes: H02J 9/005 using a power saving mode for copiers G03G15/5004
• CPC Class Codes: H02J 9/007 Detection of the absence of a load
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y04S 20/20 End-user application control systems

Abstract

A method and circuit is provided for reducing power consumption in a power transformer, typically incorporated into an electrical or electronic device such as a consumer device. In an embodiment, a detection/isolation circuit is coupled to an input of a power transformer/rectifier via a switching device. The switching device can be, for example, a solid state relay. The detection/isolation circuit is configured to sense the occurrence of no-load conditions in the power transformer and responsively disengage the power transformer from a coupled source of power (e.g., wall outlet) via the coupled switching device.

Claims

1. A circuit for reducing power consumption in a power transformer during low-load and no-load conditions, the circuit comprising:

a first solid state switching device coupled to an input of the power transformer, said first solid state switching device being configured to disengage said power transformer from a power source upon detecting said no-load and low-load conditions on said power transformer;

a second solid state switching device coupled to an output of said power transformer

a rectifier coupled to an output of said power transformer, said rectifier being configured to rectify an output voltage of said power transformer;

a super capacitor coupled in parallel to an output of said rectifier , said super capacitor being configured to store energy during a load condition and further being configured to provide energy during said low-load and no-load conditions;

a voltage sense module coupled to said super capacitor and configured to monitor continuously a voltage on said super capacitor and to output a first control signal upon detecting a low voltage condition on said super capacitor;

a current sense module coupled to an output of said power transformer, said current sense module being configured to detect a load on said power transformer and to output a second control signal upon detecting said load condition, and

a control circuit configured to receive said first control signal from said voltage sense module and to receive said second control signal from said current sense module and to output a close switch signal to said first and second solid state switching devices in response to receiving said first and second control signals;

wherein the voltage sense module and the current sense module receive power from the super capacitor.

2. A circuit according to claim 1, further comprising a regulator module for regulating power distributed to said voltage sense module, said current sense module and said control circuit.

3. A circuit according to claim 2, wherein the first and second solid state switching devices are solid state relays.

4. A circuit according to claim 1, wherein said first and second solid state switching devices open and close substantially simultaneously.

5. A circuit according to claim 1, wherein said detection of said low voltage condition comprises detecting a voltage on said super capacitor being substantially equal to a pre-determined threshold voltage.

6. A circuit according to claim 1, wherein said capacitor is on the order of 1 farad.

7. A circuit according to claim 1, wherein said power transformer is an element of a consumer device.

8. A circuit according to claim 1, wherein said low-load condition is less than substantially 5 mW.

9. A circuit according to claim 1, wherein said current sense module further comprises a sensing resistor for detecting a load on said power transformer.

10. A device having reduced power consumption during low-load and no-load conditions, comprising:

a rectifier configured to convert AC power to DC power;

a power transformer coupled to said rectifier;

a power reduction circuit configured to reduce power consumption during said low-load and no-load conditions, the power reduction circuit comprising;

(a) a first solid state switching device coupled to an input of the power transformer, said switching device configured to disengage said power transformer from a power source upon detecting said no-load and low-load conditions on said power transformer;

(b) second solid state switching device coupled to an output of said power transformer.

(c) a super capacitor coupled in parallel to an output of said power transformer, said a super capacitor being configured to store energy during a load condition and to provide energy during said low-load and no-load conditions;

(c) a voltage sense module coupled to said super capacitor and configured to monitor continuously a voltage on said super capacitor and to output a first control signal upon detecting a low voltage condition on said super capacitor;

(d) a current sense module coupled to an output of said power transformer, said current sense module being configured to detect a load on said power transformer and to output a second control signal upon detecting said load condition; and

(e) a control circuit configured to receive said first control signal from said voltage sense module, to receive said second control signal from said current sense module, and to output a close switch signal to said switching device in response to receiving said first and second control signals;

wherein the voltage sense module and the current sense module receive power from the super capacitor.

11. A device according to claim 10, wherein the first and second solid state switching devices are solid state relays.

12. A device according to claim 10, further comprising a regulator module for regulating power distributed to said voltage sense module, said current sense module and said control circuit.

13. A device according to claim 10, wherein said detection of said low voltage condition comprises detecting a voltage on said super capacitor being substantially equal to a pre-determined threshold voltage.

14. A device according to claim 10, wherein said device is a consumer device.