Circuits and methods to limit an in-rush current of a load circuit such as a processor are disclosed. A charge pump is used as driver for switches with pulse modulation width (PWM) control on the duty cycle of a clock. A clock generator generates a ramp signal with variable slope and a reference voltage. The slope of the ramp signal is dependent on the in-rush current of the switch. No dedicated slew rate driver or an external capacitor is required. The main building blocks are: a charge pump used as driver connected to single supply domain, one external (or internal) switch device, a single capacitive feedback between the switch device and the PWM control, and a PWM control comprising a fix frequency voltage triangular pulse generator with variable slope proportional to the in-rush current measurement.