Multi-mode dimmer interfacing including attach state control

摘要

A system and method includes a controller that is configured to coordinate (i) a low impedance path for a dimmer current, (ii) attaching a dimmer to a power converter system at the leading edge of a phase-cut, rectified input voltage, (iii), control of switch mode power conversion, and (iv) an inactive state to, for example, reduce the dimmer current while allowing a dimmer to function normally from cycle to cycle of an alternating current (AC) supply voltage. In at least one embodiment, the dimmer functions normally when the dimmer conducts at a correct phase angle indicated by a dimmer input setting and avoids prematurely resetting while conducting. In at least one embodiment, by coordinating functions (i), (ii), (iii), and (iv) the controller controls a power converter system that is compatible with a triac-based dimmer.

主权项

1. An apparatus comprising:
a controller configured to:
sense a leading edge of a dimmer input voltage; andafter the sensing the leading edge of the dimmer input voltage, actively control a continuous, decreasing transition of a current through a triac-based dimmer until the current through the triac-based dimmer reaches a holding current value to prevent a triac of the dimmer from prematurely resetting; wherein the controller comprises:
a multiplexer having an attach current value input and a peak current value input;a low pass filter coupled to an output of the multiplexer to generate an output signal having a decreasing transition from the attach current value to the peak current value; anda boost controller coupled to the low pass filter to control current through the dimmer in accordance with the output signal of the low pass filter.