Abstract
A programmable hysteresis comparator with tunable asymmetry for blood pressure peak detection is proposed. The hysteresis can be controlled by two programmable width transistors independently. The total current for the designed comparator is approximately 3.4 mu A with a 3.0 V supply. The hysteresis change does not affect the comparator's power consumption. The measured results show that with the flexible programming of the hysteresis, the peak detection circuit has good immunity for either 50 Hz power line noise or low frequency motion artifacts, and can be suitable for most blood pressure peak extraction cases. The design can be easily extended to the low-voltage low-power pulse counting and peak detection circuitries in other applications.