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. A method wherein a dimmer voltage to a power converter system comprises four states that occur from:
A. an approximately zero volt crossing of the dimmer voltage of a dimmer until a phase cut, leading edge of the dimmer voltage; B. an end of state A until a steady state value of a dimmer current has reached a predetermined hold value; C. an end of state B until energy transferred to a load is sufficient to meet at least one energy transfer parameter; and D. an end of state C until a beginning of state A;the method comprising:
for state A, enabling a low impedance path for a dimmer current of the dimmer,
wherein the impedance of the low impedance path is sufficiently low to maintain a stable phase angle of the dimmer; for state B:
enabling control of switch mode power conversion of the dimmer voltage;sensing a leading edge of a dimmer input voltage; andafter the sensing the leading edge of the dimmer input voltage, actively controlling a decreasing transition of a current through a triac-based dimmer to prevent a triac of the dimmer from prematurely resetting; for state C, controlling switch mode power conversion to maintain the dimmer current above a threshold; and for state D, entering an inactive state, wherein during the inactive state the low impedance path and the control of mode power conversion is disabled.