A DC control voltage being supplied to a pulse-width modulator in a switched resistor regulator control feedback loop is modified by addition of an AC offset voltage dither signal; the sum of the DC and AC voltages suffices to "turn on" the pulse-width modulator in some, but not all, of the periods of...http://www.google.com/patents/US4988942?utm_source=gb-gplus-sharePatent US4988942 - Switched resistor regulator control when transfer function includes discontinuity
