Patent ID: 7072198

Claim:
In a switching mode converter having a switching transistor and an inductor, a discontinuous mode control circuit comprising: a discontinuity detector coupled to the inductor that detects when the converter enters the discontinuous mode to generate a TRIP signal, the discontinuity detector determining the portion of a cycle of the switching transistor during which the converter is in discontinuous mode; and a feedback controller coupled to an output of the converter and to the discontinuity detector, which alters a feedback control signal of the converter responsive to the determined portion of the cycle of the switching transistor during which the converter is in discontinuous mode; and further comprising a freewheeling diode coupled to the inductor to discharge magnetic field energy stored in the inductor when the switching transistor shuts off; and wherein the discontinuity detector comprises a comparator coupled across the freewheeling diode and detecting when voltage across the diode is an appropriate polarity for reverse current flow to generate the TRIP signal.