| 摘要 |
<p>A circuit for supplying a light source (L) such as a high flux (HF) LED with Pulse Width Modulation (PWM) dimming capability includes: a rectifier (10) for receiving an input bipolar PWM modulated signal (v) representative of a desired dimming level for the light source (L) and produce therefrom a rectified signal; a current regulator (14) to receive the rectified signal and produce therefrom a supply current for the light source (L); and a control module (16) sensitive to the input bipolar PWM modulated signal (v) to control the current regulator (14) to produce a PWM modulated supply current for the light source (L); and a capacitor (18) arranged between the rectifier (10) and the current regulator (14) to stabilize the rectified signal. The circuit typically includes ancillary circuitry (12), such as a microcontroller, connected to the capacitor to be supplied with the rectified signal as stabilized by the capacitor (18). The ancillary circuitry (12) is thus supplied irrespective of the dimming level associated with the input bipolar PWM modulated signal.</p> |
