A low power CMOS current mode bandgap reference circuit with low temperature coefficient of output voltage

Abstract

In this paper a low power CMOS current mode bandgap reference (BGR) circuit with low temperature coefficient (tempco) of output voltage is presented. The conventional bandgap reference circuit typically produces an output voltage of 1.2V that prevents the low voltage operation. A T-structure bandgap core circuit being proposed in this paper is capable of operating at lower supply voltages that can also provide low temperature coefficient (tempco) of reference voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">REF</sub> ). V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">REF</sub> voltage is obtained from the sum of the two currents, one being proportional to V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BE</sub> and the other proportional to V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> . The Montecarlo simulation results show a worst case deviation of ±1.8% in the generated reference voltage of 0.54V over a temperature range of -40 to 125°C and a supply voltage range of 1.0V to 1.2V. The proposed circuit consists of a CMOS opamp, BJTs and resistors and is designed in conventional 65nm CMOS logic process.