Self-Calibrated Knee Voltage Detector With 99.65% High Accuracy for AC Charger System in 0.5 mu m 500 V UHV Process

Abstract

The self-calibrated knee voltage detector (SC-KVD) for electrical isolation primary side charger applications is proposed. The removal of the feedback network which is used in conventional designs and occupies at least 30 mm(2) can save PCB area up to around 11%. Besides, the SC-KVD can dynamically adjust the detection point to improve the accuracy to 99.65% compared to the prior arts. The test chip fabricated in 0.5 mu m 500 V UHV process can be powered on directly by the AC source owing to the 500 V ultra-high voltage device. Hence, the battery charger can be made more compact and portable than it was and the battery life can be prolonged and guaranteed.