Design of a low temperature drift bandgap reference source with curvature compensation

A low temperature drift bandgap reference source with curvature compensation was designed. The prototype was implemented with traditional amplifier clamping, two kinds of different section curvature compensation circuit were added to the circuit, node current subtracting was designed to generate a negative temperature coefficient compensation current in the low temperature phase, transistor conduction was controlled to generate a positive temperature coefficient compensation current in the high temperature phase, the curvature compensation for the reference voltage was achieved. Cascode structures were also introduced in this bandgap reference to improve the power supply rejection ratio(PSRR). Based on 0.18 μm TSMC process, the circuit was simulated with Cadence Spectre. Simulation results indicate that the output reference voltage is 1.241 V under the 3.3 V power supply. The bandgap reference voltage has a temperature coefficient of 3.02×10–6/℃ at –40–+125 ℃. The power supply rejection ratio(PSRR) is lower than –57 d B at low frequency.