A complete over-current/short-circuit protection system for Low-Drop Out regulators

A complete over-current and short-circuit protection system for Low-Drop Out (LDO) regulator applications is presented. The system consists of a current-sense circuit, a current comparator, a D Flip-Flop, an OR logic gate and the short-circuit sense topology. The protection circuit is able to shut down the LDO rapidly by producing a control signal when an over-current event occurs while during the normal operation of the LDO, the protection circuit is idle. The restart of the LDO has to be made manually and a master Reset signal is, also, available. The proposed protection system was designed by using a standard 0.18u CMOS technology using high-voltage transistors.