A low voltage CMOS bandgap reference without using an opamp

A simple low voltage CMOS bandgap voltage reference that does not require an opamp is proposed. The major advantage of this design is in its low current consumption. Most of the total current consumption in the circuit is used for generating the output voltage. To improve the line regulation as well as the robustness of the design against process variations, a technique for modifying the feedback loop in the circuit was also proposed. Such modification does not require additional die area and power consumption. The proposed techniques were demonstrated with two low voltage bandgap reference designs using a conventional 0.18 mum CMOS process. The reference that was designed with the proposed modified feedback loop achieved a temperature coefficient of Lt10 ppm/degC and a line regulation of Lt0.4 mV/V with a current consumption of ~5 muA from a 1 V supply.