Patent ID: 7906943

Claim:
A controller for a DC-to-DC power converter, the controller comprising: a modulator configured to generate a driving signal for alternately turning on and off a switching transistor, wherein the switching transistor conducts a coil current that increases while the switching transistor is on and the driving signal turns off the switching transistor after the coil current reaches a desired peak current level; a feedback comparator configured to generate a feedback signal based on comparing a target reference with a sensed signal indicative of a load condition; and a desired peak current circuit configured to generate an output to indicate the desired peak current level and to vary the desired peak current level based at least in part on the feedback signal while the controller operates in a discontinuous switching mode in which the feedback signal transitions to a first state that enables the modulator when the sensed signal is less than the target reference and transitions to a second state that disables the modulator when the sensed signal is greater than the target reference, wherein the desired peak current circuit further varies the desired peak current level responsive to a clock signal that tracks the driving signal for the switching transistor, and wherein the desired peak current circuit comprises, a clock divider or a clock counter that receives the clock signal and outputs a one-shot pulse after every M cycles of the clock signal, and a binary counter that increases by a first predefined step in response to an up signal and decreases by a second predefined step in response to a down signal, wherein an output of the binary counter indicates the desired peak current level.