LED DRIVER AND CONTROL METHOD

摘要

A DC-DC converter has a pulse width control circuit producing a sequence of pulses, with an on time, an off time and a switching frequency. The on time as well as the switching frequency are both varied in dependence on a dimming setting.

主权项

1. An LED driver comprising:
a DC-DC converter having a pulse width control circuit producing a sequence of pulses, with an on time, an off time and a switching frequency; and a control circuit having an input for receiving a dimming setting, wherein the control circuit is for controlling the pulse width control circuit to vary the on time as well as the switching frequency in dependence on the dimming setting, wherein for at least one range of dimming settings, the control circuit is adapted to vary both the on time and the switching frequency as a function of the dimming setting, the relative dominances of switching frequency variation and on-time variation being depending on the dimming setting.