Circuit and associated method for reducing power consumption in a power transformer
View Patent ↗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.
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.