A MOSFET subdivision, MOSFET-only subthreshold voltage and current reference for LDO applications

Abstract

This paper proposes a MOSFET-only voltage and current reference circuit, which can simultaneously provide a 2 V reference voltage and 300 nA reference current. This design is mainly used in a low-power Low-Dropout Regulator (LDO) project, after simulation verification, which works well in LDO applications. The circuit is performed by SMIC.18 CMOS technology and simulation with the Cadence platform, with different threshold voltage MOSFET circuit design. The whole circuit works in the subthreshold area, and the overall circuit consists of the start-up circuit, the current reference circuit, the voltage reference circuit, the MOSFET subdivision circuit, and the current mirror output circuit. The circuit has the characteristics of high precision and low power consumption, with a layout size of only 0.015 mm2. Under a temperature range of -30 to 70 °C and a power voltage of 3.3 V, the simulation and post-simulation temperature coefficients (TC) of the circuit are 5.4 ppm/°C and 19.4 ppm/°C, respectively. The post-simulation output reference voltage at room temperature is 2.0008 V, and the working power voltage within the circuit error range is 3.2 V to 3.4 V. Excluding the current mirror output circuit part of the Current-Quiescent (IQ) being 530 nA, the power consumption is 1.75 μW when the supply voltage is 3.3 V, and the design goal is reached.