Abrupt Power-Off Detector for Mobile TFT-LCD Driver IC

A circuit technique to detect unexpected power condition such as battery separation is presented. Abrupt power-off due to this unexpected power condition may cause an abnormal display in mobile TFT-LCD because adequate power-off sequence cannot be performed. To demonstrate feasibility of the APD, test chip was designed and fabricated in a 30-V/4-um 5-V/0.8-um 2.5-V/0.25-um triple-well CMOS process. Experimental results show that the proposed APD improves display quality by allowing a proper power-off sequence at all abrupt power-off conditions.