Warming dimmer controller for LED

摘要

A control circuit is provided for a light emitting diode (LED) lighting system to achieve a dim-to-warm effect. The control circuit comprises an LED controller, a clamp circuit coupled to a set of warm correlated color temperature ("CCT") LEDs, a switch coupled to a set of cool LEDs, the clamp circuit and the switch And feedback circuit. The LED controller is configured to control the clamp circuit to clamp the current through the set of warm LEDs based on the input current, and to control the switch such that the input current is greater than the first threshold level. The set of cool LEDs is turned on in response to being too large, and the set of cool LEDs is turned off in response to the input current being lower than the first threshold level. The feedback circuit is configured to divert current from the set of warm LEDs to the set of cool LEDs.