POWER CONVERSION CIRCUIT FOR LIGHT EMITTING DIODE

• US 20120119675A1
• Filed: 06/20/2011
• Published: 05/17/2012
• Est. Priority Date: 11/12/2010
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Cho, Yuan-Pin, CHANG, Wen-Ti, Chueh, Chin-Chuang, Chang, Chia-Yuan
• Granted Patent: US 8,704,457 B2
• Time in Patent Office: Days
• US Class Current: 315/294
• CPC Class Codes: H02M 1/10 Arrangements incorporating converting means for enabling loads to be operated at will from different kinds of power supplies, e.g. from ac or dc
• CPC Class Codes: H02M 3/28 using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/375 using buck topology
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A power conversion circuit for light emitting diode includes a voltage converter. The voltage converter has two receiving terminals and two output terminals. The two receiving terminals of the voltage converter are electrically coupled to the direct current power supply, and the output terminals output corresponding direct current signals according to the received direct current power supply, to drive a light emitting diode string. One of the output terminals has a positive potential, and another output terminal has a negative potential.

Claims

1. A power conversion circuit for light emitting diode, adapted to drive a light emitting diode string, the power conversion circuit comprising:

a voltage converter, having two receiving terminals and two output terminals, the two receiving terminals being electrically coupled to a direct current power supply to convert the direct current power supply to direct current output signals which are outputted from the output terminals of the voltage converter to drive the light emitting diode string, wherein one of the output terminals has a positive potential and another one of the output terminals has a negative potential.

2. The power conversion circuit for light emitting diode of claim 1, wherein the voltage converter comprises:

a first receiving terminal electrically coupled to a high potential of the direct current power supply;

a second receiving terminal electrically coupled to a low potential of the direct current power supply;

a first output terminal configured for providing an output of positive potential;

a second output terminal configured for providing an output of negative potential;

a switch having a first terminal and a second terminal, the first terminal of the switch being electrically coupled to the first receiving terminal;

a first inductor having a positive terminal and a negative terminal, the positive terminal of the first inductor being electrically coupled to the second terminal of the switch, the negative terminal of the first inductor being electrically coupled to the second receiving terminal;

a second inductor having a positive terminal and a negative terminal, the second inductor being electromagnetically coupled to the first inductor, and the negative terminal of the second inductor being maintained at a preset low potential;

a third inductor having a positive terminal and a negative terminal, the third inductor being electromagnetically coupled to the first inductor, and the negative terminal of the third inductor being electrically coupled to the second output terminal;

a first unilateral connecting component electrically coupled to the positive terminal of the second inductor and the first output terminal, and only allowing electrical current to flow from the positive terminal of the second inductor to the first output terminal;

a second unilateral connecting component electrically coupled to the positive terminal of the third inductor and the negative terminal of the second inductor, and only allowing electrical current to flow from the positive terminal of the third inductor to the negative terminal of the second inductor;

a first capacitor, one end of the first capacitor being electrically coupled to the first output terminal, and another end of the first capacitor being electrically coupled to the negative terminal of the second inductor; and

a second capacitor, one end of the second capacitor being electrically coupled to the negative terminal of the second inductor, and another end of the second capacitor being electrically coupled to the second output terminal.

3. The power conversion circuit for light emitting diode of claim 2, wherein the preset potential is the ground potential.

4. The power conversion circuit for light emitting diode of claim 1, wherein the voltage converter comprises:

a first receiving terminal electrically coupled to a high potential of the direct current power supply;

a second receiving terminal electrically coupled to a low potential of the direct current power supply;

a first output terminal configured for providing an output of positive potential;

a second output terminal configured for providing an output of negative potential;

a potential booster electrically coupled to the first receiving terminal and the second receiving terminal to receive the direct current power supply, and having its output terminal served as the first output terminal;

an inverse potential booster electrically coupled to the first receiving terminal and the second receiving terminal to receive the direct current power supply, and having its output terminal served as the second output terminal.

5. The power conversion circuit for light emitting diode of claim 4, wherein the potential booster comprises:

an inductor having a first terminal and a second terminal, the first terminal of the inductor being electrically coupled to the first receiving terminal;

a switch electrically coupled to the second terminal of the inductor and the second receiving terminal;

a unilateral connecting component electrically coupled to the second terminal of the inductor and the first output terminal, and only allowing electrical current to flow from the second terminal of the inductor to the first output terminal; and

a capacitor electrically coupled to the first output terminal and the second receiving terminal.

6. The power conversion circuit for light emitting diode of claim 4, wherein the inverse potential booster comprises:

a switch having a first terminal and a second terminal, the first terminal electrically coupled to the first receiving terminal;

an inductor electrically coupled to the second terminal of the switch and the second receiving terminal;

a unilateral connecting component electrically coupled to the second terminal of the switch and the second output terminal, and only allowing electrical current to flow from the second output terminal to the inductor; and

a capacitor electrically coupled to the second output terminal and the second receiving terminal.