The typical current mode bandgap voltage circuit is built up by two currents, one is proportional to V{sub}(BE) across the base-emitter of the parasitic BJT in CMOS process, the other is proportional to V{sub}T. The negative temperature coefficient of the former term compensates the positive temperature coefficient of the latter. But the temperature dependence of V{sub}(BE) is not linear and therefore doesn't completely cancel the linear temperature dependence of △V{sub}(BE), which is proportional to absolute temperature (PTAT). A curvature-compensated bandgap reference (BGR) with 1.8-V supply voltage is presented, which utilizes the different temperature-dependent emitter of the BJT to obtain the nonlinear current I{sub}(NL) to cancel the nonlinear term of I{sub}(VBE). The simulation results indicate the temperature coefficient (TC) of 8ppm/°C from -40°C to 80°C and a higher power supply rejection ration (PSRR) using 0.18um CMOS process. A scaled-down bandgap reference voltage can also be obtained by setting the resistor and current mirror in the proposed BGR circuit.
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