METHOD AND CIRCUITRY FOR DETECTING A LEADING-EDGE PHASE-CUT DIMMER

摘要

In described examples, a dimmer detector (300) includes an edge detector (340) that detects whether an input signal (Vin) has a rapidly rising edge and generates an output signal pulse if a rapidly rising edge is detected. If the edge detector (340) outputs a signal pulse, a pulse stretcher (330) generates a stretched pulse having a duration that is longer than the signal pulse received from the edge detector (340). If the pulse stretcher (330) output signal includes at least a predetermined number of stretched pulses within a predetermined amount of time, a dimmer detect signal (DIM DET) signals the presence of a leading-edge phase-cut dimmer.