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 LED.Three discrete constant current settings are ...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 LED.Three 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 A.An autozero transconductance amplifier is proposed,which effectively improves the precision,reduces the offset voltage and the noise.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.展开更多
基金supported by the National Natural Science Foundation of China(No. 60876023)
文摘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 LED.Three 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 A.An autozero transconductance amplifier is proposed,which effectively improves the precision,reduces the offset voltage and the noise.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.
