An Error Amplifier with Wide Input Common Mode Voltage Range for HBWLED Driver
Xiaobo Wu · 2009
A novel error amplifier based on high side current sensing was proposed for driver controller of high brightness white(HBW) LED arrays,which require a high input common mode voltage(ICMR).The improved circuit architecture makes the amplifier have adjustable offset voltage to control load currents for LED dimming.The chip was designed and simulated in 1.5 μm BiCMOS HV process.Simulation results showed that the circuit had an ICMR from 3 V to 50 V,a CMRR(common mode rejection ratio) of 80 dB,and an adjustable offset voltage from 8 mV to 92 mV.Test results indicated that the major performance of the circuit reached the design target.