A switching regulator, which applies output DC voltage to a load via an oscillator oscillatable between ON and OFF states, has an oscillation controller to control the oscillation of the oscillator based on the load so that a frequency of the oscillating of the oscillator is kept lower than a predetermined...http://www.google.co.uk/patents/US5175675?utm_source=gb-gplus-sharePatent US5175675 - Switching regulator in which oscillation is maintained below a predetermined frequency
