Hysteretic mode LED driver with precise average current

摘要

A hysteretic mode LED driver for providing a driving current for an LED includes a hysteretic comparing circuit and a feedback loop. The hysteretic comparing circuit compares a driving current related sensing signal with a reference signal to control the average value of the driving current. The feedback loop senses the error between the average value of the driving current and a target value to adjust the reference signal or the offset of the hysteretic comparing circuit to adjust the average value of the driving current.

主权项

1. A hysteretic mode LED driver for providing a driving current for an LED, comprising:
a power stage operative to generate the driving current; a first sensor connected to the power stage, operative to sense the driving current to generate a first sensing signal; a first signal source operative to provide a first reference signal; a hysteretic comparing circuit connected to the power stage, the first sensor and the first signal source, operative to generate a control signal according to the first sensing signal and the first reference signal for the power stage to control a peak value and a valley value of the driving current; a second signal source operative to provide a second reference signal; and a feedback loop connected to the first and second signal sources, operative to generate a feedback signal according to the second reference signal and a second sensing signal related to the driving current for the first signal source to adjust the first reference signal.