Patent ID: 8797010

Claim:
A startup circuit for controlling initial current in a DC/DC switching regulator, comprising an input for receiving power from a primary power source, an output adapted to be connected to a load, a first pair of switches connected together at a first midpoint node, each having a control terminal, and the pair having first and second terminals, wherein the first terminal receives power from the primary power source and the second terminal is connected to ground, and the load receives power during normal operation via the midpoint node, driver logic connected to each of the control terminals of the pair of switches, a reference signal generator including second switch logic for selectively enabling a single preset voltage to be applied from the time voltage is initially applied to the regulator until the voltage at the output reaches substantially the intended regulated voltage to one of a group comprising a comparator, a pulse width modulator, and a pulse frequency modulator for controlling the duration of the on or off times of the first pair of switches to gradually increase the power applied by the primary power source to the load without the use of an external capacitor to control the increase.