Switched mode power supply

摘要

A switched mode power supply comprising: a rectified voltage terminal and a rectified ground terminal for receiving a phase-cut rectified voltage; a power switch and an inductive element connected in series between the rectified voltage terminal and the rectified ground terminal; a switch controller having a floating ground terminal and a dimming input terminal, wherein the dimming input terminal is for receiving a dimming voltage signal indicative of a required dimming level, wherein the switch controller is configured to control the switch in accordance with the dimming voltage signal and wherein the inductive element is connected between the rectified ground terminal and the floating ground terminal; and a dimming level controller configured to set the dimming voltage signal in accordance with the rectified phase-cut voltage with respect to the floating ground terminal.

主权项

1. A switched mode power supply, comprising:
a rectified voltage terminal and a rectified ground terminal for receiving a phase-cut rectified voltage; a power switch and an inductive element connected in series between the rectified voltage terminal and the rectified ground terminal; a switch controller having a floating ground terminal and a dimming input terminal, wherein the dimming input terminal is for receiving a dimming voltage signal indicative of a required dimming level, wherein the switch controller is configured to control the switch in accordance with the dimming voltage signal and wherein the inductive element is connected between the rectified ground terminal and the floating ground terminal; and a dimming level controller configured to set the dimming voltage signal as an average of a portion of the rectified phase-cut voltage with respect to the floating ground terminal over one or more half cycles of the phase-cut rectified voltage.