A low power programmable band gap reference circuit with subthreshold MOSFETs

In this paper, a novel approach is proposed for the design of low power CMOS programmable band gap reference circuit. In the literature, an inversion technique is proposed to make the voltage reference to be independent of temperature by using parasitic bipolar transistors. In the above technique, this paper proposes the use of MOSFETs operating in subthreshold region for generating a voltage with negative temperature coefficient. Programmability is proposed for the first time by changing the aspect ratio, the current flowing through diode connected MOSFETs and gain introduced through the inversion technique. To study the performance of the proposed programmable scheme, the band gap reference is implemented in tsmc035 CMOS process with 3.7 V power supply. The simulation carried out in Eldo spice indicates that temperature coefficients are 7 ppm/ldrc, 23 ppm/ldrc and 30 ppm/ldrc respectively over the temperature range of -10ldrc to 120ldrc for output voltages 0.9 V, 1.2 V and 1.5 V. It dissipates 53 muW, 134 muW and 302 muW for output voltages 0.9 V, 1.2 V and 1.5 V respectively. The estimated silicon area is 0.023 mm².