The LM78S40 is a monolithic regulator subsystem consisting
of all the active building blocks necessary for switching regulator
systems. The device consists of a temperature compensated
voltage reference, a duty-cycle controllable oscillator
with an active current limit circuit, an error amplifier, high
current, high voltage output switch, a power diode and an
uncommitted operational amplifier. The device can drive external
NPN or PNP transistors when currents in excess of
1.5A or voltages in excess of 40V are required. The device
can be used for step-down, step-up or inverting switching
regulators as well as for series pass regulators. It features
wide supply voltage range, low standby power dissipation,
high efficiency and low drift. It is useful for any stand-alone,
low part count switching system and works extremely well in
battery operated systems.