Power systems for driving light emitting diodes and associated methods of control

摘要

Embodiments of LED driver circuits and the associated methods are disclosed herein. In one embodiment, the LED driver circuit comprises a switch-mode converter, a controller, a feedback circuit, and a gating circuit. The feedback circuit includes a current balance circuit. The gating circuit is responsive to both a current feedback signal and a voltage feedback signal and is configured to select one of them as the feedback signal.

主权项

1. A light emitting diode (LED) driver circuit, comprising:
a switch-mode converter comprising a power transfer device and a switch device, the switch-mode converter having an output end configured to supply power to an LED load; a controller having an input end and an output end, wherein the output end is coupled to the switch device of the switch-mode converter; and a feedback circuit coupled between the output end of the switch-mode converter and the input end of the controller, wherein the feedback circuit comprises a current sensing circuit having an output providing a sensed current signal representative of a current flowing through the LED load, a voltage sensing circuit having an output providing a sensed voltage signal representative of an output voltage of the switch-mode converter, and a gating circuit, wherein the gating circuit has a first input end coupled to the output of the current sensing circuit, a second input end coupled to the output of the voltage sensing circuit, and an output end coupled to the input end of the controller to provide an output signal thereto, wherein the output signal is generated based on the sensed current signal when the output voltage is lower than an over-voltage threshold, and based on the sensed voltage signal when the output voltage is higher than the over-voltage threshold.