UC2543

www.ti.com UC1543, UC1544 UC2543, UC2544 UC3543, UC3544 SLUS188A – APRIL 1997 – REVISED FEBRUARY 2007 Power Supply Supervisory Circuit FEATURES Includes Over-Voltage, Under-Voltage, and Current Sensing Circuits Internal 1% Accurate Reference Programmable Time Delays SCR “Crowbar” Drive of 300 mA Remote Activation Capability Optional Over-Voltage Latch Uncommitted Comparator Inputs for Low Voltage Sensing (UC1544 Series Only) DESCRIPTION The monolithic integrated circuits contain all the functions necessary to monitor and control the output of a sophisticated power supply system. Over-voltage (O.V.) sensing with provision to trigger an external SCR “crowbar” shutdown; an undervoltage (U.V.) circuit which can be used to monitor either the output or to sample the input line voltage; and a third op amp/comparator usable for current sensing (C.L.) are all included in this device, together with an independent, accurate reference generator. Both over- and under-voltage sensing circuits can be externally programmed for minimum time duration of fault before triggering. All functions contain open collector outputs which can be used independently or wire-or’ed together, and although the SCR trigger is directly connected only to the over-voltage sensing circuit, it may be optionally activated by any of the other outputs, or from an external signal. The O.V. circuit also includes an optional latch and external reset capability. The UC1544/2544/3544 devices have the added ...