A 409mV, Sub-10nW Power-on Reset Circuit Using Adaptive Accuracy Adjustment for Low Voltage Applications

A low power power-on reset (POR) circuit with low temperature coefficient, low quiescent current and small area is proposed in this paper. The POR circuit samples the power supply voltage through a high threshold transistor and then converts the voltage to a current, which will be compared with a native NMOS based current reference to obtain the reset signal. In order to reduce the power consumption in steady state, an adaptive accuracy adjustment mechanism is employed in the proposed POR circuit. The POR circuit uses a low accuracy but energy efficient structure to monitor the supply voltage in steady state, and when a voltage drop is observed, the POR circuit quickly switches to a high accuracy mode to get an accurate brown-out detection trip voltage. The POR circuit is implemented in 55nm CMOS process and the active area is just 107μm
²
. Post-layout simulation results show that the POR circuit has a POR trip voltage of 409mV, a static power of 9.11nW at a supply voltage of 0.45V. Besides, the temperature coefficient of the proposed POR circuit is only 31.76μV/°C over a temperature range of -40°C to 125°C.