Power supply circuit having standby detection circuit

• US 20090251205A1
• Filed: 04/03/2009
• Published: 10/08/2009
• Est. Priority Date: 04/03/2008
• Status: Active Grant

• Current Assignee: InnoLux Corporation
• Original Assignee: Innolux Display Corporation (InnoLux Corporation)
• Inventors: Lin, Ching-Chung
• Granted Patent: US 8,085,016 B2
• Time in Patent Office: Days
• US Class Current: 327/544
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: G06F 1/3265 Power saving in display device
• CPC Class Codes: G06F 1/3287 by switching off individual functional units in the computer system
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A power supply circuit includes a voltage output controller configured for outputting voltages, a standby controller configured for directing the voltage output controller to provide voltage to a load, and a microprocessor configured for controlling the standby controller according to a mode of the load. The voltage output controller is applied with a direct current voltage. When the load enters active mode from a powered off mode, the standby controller sends a control signal to the voltage output controller to output direct current voltage to the load and the microprocessor. When the load enters standby mode from the active mode, the microprocessor directs the standby controller to prevent the voltage output controller from outputting direct current voltage to the load and the microprocessor.

Claims

1. A power supply circuit, comprising:

a voltage output controller comprising a first switching element and a second switching element;

a standby controller, comprising a trigger and a third switching element, the trigger comprising an input terminal and an output terminal;

a standby detection circuit configured for detecting a mode of a load, the standby detection circuit comprising an input terminal and two output terminals; and

a microprocessor comprising a first input terminal, a second input terminal, and an output terminal;

wherein each of the first, second, and third switching elements comprises an input terminal, an output terminal, and a control terminal, each input terminal of the second and the third switching elements being applied with a direct current voltage, the input terminal of the first switching element being connected to ground, the output terminal of the first switching element being connected to the control terminal of the second switching element, the control terminal of the first switching element being connected to the output terminal of the third switching element, the output terminal of the second switching element being connected to the load, and the first input terminal of the microprocessor, the input terminal of the standby detection circuit being connected to the load, the two output terminals of the standby detection circuit being connected to an input terminal of the microprocessor and the input terminal of the trigger, the output terminal of the trigger being connected to the control terminal of the third switching element and the input terminal of the microprocessor, wherein when the input terminal of the standby detection circuit detects the load entering an active mode from a power off mode, the standby detection circuit sends a control signal to the trigger, the trigger generating a voltage to turn on the third switching element, the direct current voltage being applied to the first switching element via the third switching element, the first and the second switching elements being turned on sequentially, the direct current voltage being applied to the load and the microprocessor via the second switching element, wherein when the standby detection circuit detects the load entering a standby mode from the active mode, the standby detection circuit sends another control signal to the microprocessor, the microprocessor controlling the third switching element, and the first and the second switching elements to be turned off sequentially such that power is restricted from reaching the load and the microprocessor, the power supply circuit being in the standby mode.

2. The power supply circuit of claim 1, wherein the third switching element comprises a transistor, a base electrode of the transistor being connected to the output terminal of the trigger, a collector electrode of the transistor being applied with the direct current voltage, and an emitter electrode of the transistor being connected to the control terminal of the first switching element.

3. The power supply circuit of claim 2, wherein the transistor is an NPN transistor.

4. The power supply circuit of claim 1, wherein the first switching element comprises a transistor, the base electrode thereof being connected to the output terminal of the third switching element, an emitter electrode thereof the transistor being connected to ground, and a collector electrode thereof being connected to the control terminal of the second switching element.

5. The power supply circuit of claim 4, wherein the transistor is an NPN transistor.

6. The power supply circuit of claim 1, wherein the second switching element comprises a transistor, a base electrode thereof being connected to the output terminal of the first switching element and an emitter electrode thereof, the collector electrode thereof being connected to the load and the input terminal of the microprocessor, and the emitter electrode thereof being applied with the direct current voltage.

7. The power supply circuit of claim 1, further comprising a voltage converter, the voltage converter for receiving an alternating voltage from an external circuit, and outputting direct current voltage to the input terminals of the second and the third switching elements.

8. The power supply circuit of claim 7, wherein the voltage converter comprises a switching controlling circuit, a transistor, and a transformer, the switching controlling circuit for controlling a turn on period of the transistor, so as to adjust the output voltage of the transformer.

9. The power supply circuit of claim 1, further comprising a standby indication circuit configured for indicating a standby mode of the power supply circuit.

10. A power supply circuit, comprising:

a voltage output controller, comprising a first switching element and a second switching element;

a standby controller, comprising a trigger, a third switching element, and a manual switch, the trigger comprising an input terminal and an output terminal; and

a microprocessor comprising an input terminal, and an output terminal;

wherein each of the first, the second, and the third switching elements comprises an input terminal, an output terminal, and a control terminal, each input terminal of the second and the third switching elements being applied with a direct current voltage, the input terminal of the first switching element being connected to ground, the output terminal of the first switching element being connected to the control terminal of the second switching element, the control terminal of the first switching element being connected to the output terminal of the third switching element, the output terminal of the second switching element being connected to the load and the first input terminal of the microprocessor, the input terminal of the trigger being connected to the manual switch, the output terminal of the trigger being connected to the control terminal of the third switching element and the output terminal of the microprocessor, wherein activation of the manual switch generates a first control signal then provided to the trigger, the trigger generating a voltage signal to turn on the third switching element, the direct current voltage being applied to the first switching element via the third switching element, the first and the second switching elements being turned on sequentially, the direct current voltage being applied to the load and the microprocessor via the second switching element, the power supply circuit entering an active mode from a powered off mode; and

upon a subsequent activation of the manual switch, a second control signal is generated and applied to the microprocessor, the microprocessor turning off the third, the first, and the second switching elements sequentially, the second switching element stopping voltage to the load and the microprocessor, and the power supply circuit entering a standby mode from the active mode.

11. The power supply circuit of claim 10, wherein the third switching element comprises a transistor, a base electrode which is connected to the output terminal of the trigger, a collector electrode of which is applied with the direct current voltage, and an emitter electrode of which is connected to the control terminal of the first switching element.

12. The power supply circuit of claim 11, wherein the transistor is an NPN transistor.

13. The power supply circuit of claim 10, further comprising a voltage converter, the voltage converter receiving an alternating voltage from an external circuit, and outputting direct current voltage to the input terminals of the second and the third switching elements.

14. The power supply circuit of claim 10, further comprising a standby indication circuit configured for indicating a standby mode of the power supply circuit.

15. A power supply circuit, comprising:

a voltage output controller configured for outputting voltages;

a standby controller configured for controlling the voltage output controller whether to provide voltage to a load; and

a microprocessor configured for controlling the standby controller according to a mode of the load;

wherein the voltage output controller is applied with a direct current voltage, and when the load enters an active mode from a powered off mode, the standby controller sends a control signal to the voltage output controller to output direct current voltage to the load and the microprocessor, and when the load enters a standby mode from the active mode, the microprocessor controls the standby controller to prevent the voltage output controller from outputting direct current voltage to the load and the microprocessor.

16. The power supply circuit of claim 15, further comprising a standby detection circuit, configured for detecting the mode of a load.

17. The power supply circuit of claim 16, wherein the standby controller comprises a manual switch, configured for alternating between an active mode and a standby mode.