Abstract: A DC to DC power converter (58) and method of controlling the DC to DC power converter (58). The converter (58) has a first switch (S.sub.1) coupled to a second switch (S.sub.2). The converter (58) is adapted to receive an input voltage V.sub.in, generate an output voltage V.sub.out, and operate at a switching frequency. A hysteretic mode control circuit (52) includes a first circuit generating a ramp signal at input (56) for controlling the converter (58). The first circuit includes a first capacitor (C.sub.1) with the ramp signal generated at an end of the first capacitor (C.sub.1). The hysteretic mode control circuit (52) is coupled to the first (S.sub.1) and second (S.sub.2) switches, where the switching frequency of the first and second switches is dependent upon the ramp signal (56) determined by the value of the components of the first circuit rather than on the voltage from the output filter of the DC to DC power converter.