摘要：Owing to the fact that the LED drive circuit must have constant output current control,we propose a controlled current driver with a high precision for the white light *** discrete constant current settings are available and may be selected at the supply voltage from 2.9 V to 4.4 V,which is up to 1 *** autozero transconductance amplifier is proposed,which effectively improves the precision,reduces the offset voltage and the *** variation in the ratio of the external resistor current to the LED load current is less than 2.3%,when the LED load current changes from 200 mA to 800 mA.