The NTE1720 PWM switching regulator control circuit contains all the essential circuitry to implement singleended or pushpull switching regulators. Included on the circuit are oscillator, voltage reference, a pulse width modulator, error amplifier, overload protection circuitry and output drivers. A substance zener reference has been used to provide excellent stability with time and the reference has been used to provide excellent stability with time and the reference is trimmed at the wafer level to provide an initial accuracy of 2%. Additionally, the oscillator is trimmed to provide a medium tolerance of 6%. Features: