Driver systems for driving light emitting diodes and associated driving methods

摘要

LED driver systems and associated methods of control are disclosed herein. In one embodiment, the LED driver system comprises a converter and a controller. The controller is responsive to the LED current feedback signal and a dimming signal, and operable to generate a continuous gate drive signal to control the primary side switch of the converter. Thus, the controller regulates the output current of the converter.

主权项

1. A light emitting diode (LED) driver system, comprising:
a switch-mode voltage converter comprising a primary switch and an output end, wherein the output end is configured to supply a current to an LED; a dimming module comprising a dimming switch coupled to the LED; and a controller configured to generate a continuous PWM drive signal to control the primary switch of the switch-mode voltage converter, and to generate a PWM dimming signal to control the dimming switch in response to an external dimming signal and a feedback signal from the output end of the switch-mode voltage converter, wherein the controller comprises a hold-on circuit configured to generate an output signal based on the feedback signal and the PWM dimming signal, wherein the output signal is in proportion to the feedback signal when the PWM dimming signal is at a first state, and wherein the output signal remains at the same value as at an end of the first state when the PWM dimming signal is at a second state, and wherein the PWM drive signal is generated in response to the output signal.