Battery-powered wearable IoT devices like fitness trackers and other blue tooth low energy devices used for health monitors, requires an accurate voltage reference circuits with minimal power consumption and higher thermal stability for any PVT variations. However, conventional bandgap reference (BGR) designs have to rely on curvature compensation or trimming techniques to overcome fundamental trade-off between accuracy, power consumption, and circuit complexity. This work presents a low-power, high-stability CMOS bandgap reference employing an analytical design approach for predictable and optimized performance. The proposed architecture integrates a zero-temperature-coefficient (ZTC) current generator with temperature-compensated resistor network to generate constant voltage reference and uses a constant-gₘ bias circuit, as part of dual stage self-timed startup mechanism. The proposed architecture further incorporated with post-regulation stage to enhance output accuracy and power supply rejection. Simulation results show stable voltage reference of 1.2 V with a temperature coefficient of 7.3 ppm/°C over temperature of −40°C to 85°C, with a current consumption of 13.9 µA. The proposed architecture achieves gain over 100dB with phase margin above 70° and PSRR of -42.1dB @ 100kHz with NSD 0.15 nV/√Hz at 1 MHz. The design is analysed analytically and demonstrated using a CR2032 coin cell as a representative case, this indicates that the proposed BGR helps to improve battery lifetime approximately a threefold of its battery lifetime, extending operation from 7.25 months to about 22 months.
R et al. (2026) studied this question.