A 36 ppm/℃ BiCMOS current reference without requiring curvature-compensation

摘要

A low temperature coefficient and high precision current reference generator, with simplified current biasing circuit with only four MOSFETs, has been designed using CSMC's 0.5 μm BiCMOS process. Utilizing source follower and emitter follower as the bandgap reference output stage, a high performance bandgap reference with no Early effect and low output resistance is realized. A one diode-connected circuit is introduced to further simplify the current biasing. Simulation results of the proposed current reference generator indicate that the output current of 2 μA exhibit a variation of 0.5% over the temperature range of -40 to 125℃ is achieved. The current reference draws 21 μA from a 5 V supply. Corner and two hundred runs Monte Carlo simulation show that the maximum deviation from the desired value of the reference current are less than 3.05% and ± 2.6%, respectively. This high precision current reference generator is intended for Organic LED driver circuits.