POWER SUPPLY CIRCUIT FOR DRIVING LED LAMP AND POWER SUPPLY METHOD, AND PRIMARY-SIDE CONTROL CIRCUIT OF FLYBACK TRANSFORMER

摘要

The present invention discloses a power supply circuit for driving an LED lamp and a power supply method. The power supply circuit is constituted by an AC-DC converter by adopting DCM-DCM. Also, the power supply circuit adopts a valley fill circuit to reduce rippling of output current and adopts the DCM-DCM to stabilize a link voltage, thereby realizing a power factor correction circuit having two-stage structures. Thus, an input voltage of the flyback converter may be improved, and a high reverse voltage may be applied.

主权项

1. A power circuit for driving an LED lamp, comprising:
a rectification circuit that outputs a rectified voltage; a boost inductor that outputs a boost current corresponding to the rectified voltage; a flyback transformer that outputs an output current corresponding to an input current of a primary side from a secondary side; a switching circuit that is switched by a pulse type signal to control a flow of the input current of the primary side of the flyback transformer; a valley fill circuit that selectively performs providing of the input current to the flyback transformer by energy accumulated in the valley fill circuit and accumulating of the energy in the valley fill circuit by using the boost current, according to switching of the switching circuit; and a boost switching circuit that selectively performs providing of a path for increasing the boost current to the boost inductor and providing of a path for providing the input current by the energy accumulated in the valley fill circuit to the primary side of the flyback transformer, according to the switching of the switching circuit.