Low power, variable supply CMOS comparator

The design of a variable supply CMOS comparator using AMS^® 0.35 μm technology is presented. The comparator is optimized for a DC-DC converter used in low power portable communication applications. The designed comparator can operate well between 1 V and 3 V supply voltages. The circuit topology is chosen with optimized parameters such that hysteresis can easily be introduced when operating in a noisy environment. Simulation results indicate that propagation delay can be as low as 4.9 nsec and input offset voltage less than 1 mV, depending on input overdrive and supply voltages. These results indicate that the use of this comparator in high-speed communication applications is possible. Temperature stability of the comparator has also been analyzed and is shown to be satisfactory in the range of -55 °C to 155 °C.