Power supply circuit for a cold-cathode fluorescent lamp
AssigneeChi Mei Optoelectronics Corp.
InventorShwang-Shi Bai
Life of this patent
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Abstract
A power supply circuit for a cold-cathode fluorescent lamp (CCFL). The power supply circuit converts a DC voltage to a high AC voltage for driving the CCFL. The power supply circuit includes: a switch; a switch control circuit for controlling the switch; a transformer for stepping up the voltage; an energy-preserving unit coupled to the transformer and the DC voltage output circuit; a first diode coupled to the transformer, the energy-preserving unit, and the switch; and a decoupling capacitor coupled to the transformer for outputting the high AC voltage.
Claims11
A power supply circuit for a cold-cathode fluorescent lamp (CCFL), the power supply circuit being coupled to a DC (Direct Current) voltage output circuit and the CCFL, the DC voltage output circuit outputting a low DC voltage, and the power supply circuit converting the low DC voltage to a high AC voltage for driving the CCFL, the power supply circuit comprising:
- a switch comprising a control node, a ground node, and a signal node;
- a switch control circuit coupled to the control node, for outputting a control signal to control the on/off status of the switch;
- a transformer having a primary side and a secondary side, the primary side having a first node and a second node, the secondary side having a third node and a fourth node, the first node coupled to the DC voltage output circuit, the second node coupled to the signal node of the switch;
- an energy-preserving unit for preserving electrical energy, having a fifth node and a sixth node, the fifth node being coupled to the first node of the primary side of the transformer and the DC voltage output circuit;
- and
- a decoupling capacitor coupled to the third node of the secondary side of the transformer for outputting the high AC voltage.
Dependencies are inferred from the claim text.