LED driver system with dimmer detection

摘要

An LED driver system including an input receiving a rectified AC conductive angle modulated voltage on a rectified node, a converter, a low-pass filter, and AC detector, and a driver network. The converter is coupled to the rectified node and includes a power switching device coupled to a switching node, in which the power switching device is controlled to convert the rectified AC conductive angle modulated voltage to an output voltage and output current. The low-pass filter is configured to filter voltage of the switching node to provide a filtered voltage. The AC detector receives the filtered voltage and provides a current sense signal indicative thereof. The driver network controls duty cycle of the power switching device based on the current sense signal.

主权项

1. An LED driver system, comprising:
an input receiving a rectified AC conductive angle modulated voltage on a rectified node; a converter coupled to said rectified node and including a power switching device coupled to a switching node, wherein said power switching device is controlled to toggle voltage of said switching node between a low voltage level to said rectified AC conductive angle modulated voltage and to convert said rectified AC conductive angle modulated voltage to an output voltage and an output current; a low-pass filter configured to filter said voltage of said switching node to provide a filtered voltage having a duty cycle indicative of a conduction angle of said rectified AC conductive angle modulated voltage; an AC detector which receives said filtered voltage and provides a current sense signal indicative of said duty cycle of said filtered voltage; and a driver network which controls said power switching device based on said current sense signal.