Method and apparatus for on/off control of a power converter

摘要

A power converter (100) controller includes feedback sampling circuitry (170) generating feedback signal samples from the controller output after a conduction of a power switch (120) is terminated. A switch conduction control circuitry (185), coupled to the feedback sampling circuitry (170), enables or disables the conduction of the power switch (120) during a switching cycle in response to the feedback signal samples. The power switch (120) is caused to conduct during at least a portion of an enabled switching cycle and prevented from conducting during an entirety of a disabled switching cycle. Optionally, switch conduction termination circuitry terminates the conduction of the power switch (120) during enabled switching cycles in response to the current through the power switch (120). Switch conduction scheduling circuitry determines a varying number of future enabled and disabled switching cycles in response to the feedback signal samples from a present and one or more past switching cycles.