Constant current control for an LED driver circuit using a microcontroller-based oscillator controlled by a differential error feedback signal from a proportional and integration control loop

摘要

A constant current driver circuit is operable to provide power to a light source. The driver circuit utilizes a microcontroller based oscillator to drive a current source tank circuit. The microcontroller based oscillator is controlled by a differential error feedback signal. The differential error feedback signal is produced by a proportional integral control loop. The proportional integral control loop is used to eliminate steady state error of the driver circuit. Dynamic frequency or duty cycle control of the current source tank circuit by the microcontroller is based on the integrated error signal between a reference current signal and a sensed output current of the current source tank circuit.