Current Reference with Low Temperature Drift and Low Power Supply
Jiang Ya-dong · Modern Electronics Technique · 2009
A current reference is designed,which owns small temperature coefficient and dissipates very low power.Temperature compensation is achieved from a bandgap circuit in order to generate an intermediate voltage reference VREF.This voltage is applied to the gate of NMOS output transistor.Such that,this output transistor is biased at Zero Temperature Coefficient(ZTC) point.Then,a temperature-independent current reference IREF is produced by mutual compensation of mobility and threshold voltage variations.This circuit implemented in CSMC 0.5μm double poly triple metal CMOS technology,The result indicates a ZTC point at VZTC of 1.244 4 V and an IZTC of 215.4 μA.A temperature coefficient of 8.1 ppm/°C from-45~+125 ℃ achieved.The power dissipation of the circuit is only 0.45 mW with 2V supply.