LED DRIVER WITH EXTENDED DIMMING RANGE AND METHOD FOR ACHIEVING THE SAME

摘要

A circuit for powering of a Light Emitting Diode (LED) string has a switching power converter. A brightness control circuit is coupled to the switching power converter to allow a duration of a conductive state of the power converter to exceed a duration of a conductive state of the LED string for maintaining a current magnitude in the LED string constant.

主权项

1. A method of achieving wide dimming range in an LED driver of a boost type having an inductor and a current control feedback comprising:
storing a state of a current control feedback upon a falling edge of the PWM signal; and disabling switching of the LED driver after the falling edge of the PWM signal and upon an inductor meeting a reference corresponding to a stored state of a current control feedback.