DESCRIPTION

M51995A is the primary switching regulator controller which is especially designed to get the regulated DC voltage from AC power supply. This IC can directly drive the MOS-FET with fast rise and fast fall output pulse. Type M51995A has the functions of not only high frequency OSC

and fast output drive but also current limit with fast response and high sensibility so the true fast switching regulator can be realized. It has another big feature of current protection to short and over current,owing to the integrated timer-type protection circuit,if few parts are added to the primary side. The M51995A is equivalent to the M51977 with externally resettable OVP(over voltage protection)circuit.

FEATURES

♦ 500kHz operation to MOS FET

•Output current...............................................................±2A

•Output rise time 60ns,fall time 40ns

•Modified totempole output method with small through current

♦ Compact and light-weight power supply

•Small start-up current............................................90µA typ.

•Big difference between start-up voltage and stop voltage makes the smoothing capacitor of the power input section small. Start-up threshold 16V,stop voltage 10V

•Packages with high power dissipation are used to with-stand the heat generated by the gate-drive current of MOS FET. 16-pin DIP,20-pin SOP 1.5W(at 25°C)

♦ Simplified peripheral circuit with protection circuit and built-in large-capacity totempole output

•High-speed current limiting circuit using pulse-by-pulse method(Two system of CLM+pin,CLM-pin)

•Protection by intermittent operation of output over current................................................................Timer protection circuit

•Over-voltage protection circuit with an externally re-settable latch(OVP)

•Protection circuit for output miss action at low supply voltage(UVLO) High-performance and highly functional power supply

•Triangular wave oscillator for easy dead time setting