A low-power microcontroller having a 0.5-μA standby current on-chip regulator with dual-reference scheme

We present a microcontroller having a 0.5-μA standby current on-chip regulator. To break through the area overhead problem which a conventional regulator scheme suffers from to achieve small standby current, we propose a dual-reference scheme in which one voltage reference circuit is provided for active mode and another voltage reference circuit is provided for standby mode. For the voltage reference circuit for standby mode, a resistor-free circuit was used to achieve small current consumption without occupying large area. The microcontroller was fabricated in a 0.18-μm CMOS process. The implementation and measurement results show that the dual-reference scheme achieves 0.5-μA current consumption of the regulator in standby mode with 50% smaller area than the conventional scheme. The measured standby current of the whole chip was 2.0 μA.