Rail-to-Rail Dynamic Voltage Comparator Scalable down to pW-Range Power and 0.15-V Supply

An ultra-low voltage, ultra-low power rail-to-rail dynamic voltage comparator solely based on digital standard cells is presented. Thanks to its digital nature, the comparator can be designed and integrated with fully-automated digital design flows and can operate at very low voltages down to deep sub-threshold. Measurements on an 180nm testchip show correct operation under rail-to-rail common-mode input at a supply voltage ranging from 0.6V down to 0.15V. The comparator delay (power) is lower than 442us (10pW) at 0.15-V supply voltage. The input offset voltage is less than 30mV over the entire rail-to-rail common-mode input and supply range. The minimum supply voltage and power are the lowest reported to date, and make the circuit suitable for direct powering from mm-scale harvesters.