Integrated circuit switching power supply controller with selectable buck mode operation

摘要

An integrated circuit (IC) controller for a switching power supply has a selectable operating mode for supporting multiple switching power supply topologies. The IC controls current by controlling a cycle rate of the switching power supply to provide a constant or variable output current, which may be provided to lighting devices such as light-emitting diodes (LEDs). The selectable operating mode includes at least a buck converter operating mode and another operating mode, which may be a flyback converter operating mode.

主权项

1. An integrated circuit for controlling a power supply circuit that generates an output current, the integrated circuit comprising:
an input for receiving a signal from a winding of a magnetic storage element of the power supply circuit; a detection circuit coupled to the input for processing the signal from the winding of the magnetic storage element to detect a duration of a flyback interval during which the magnetic storage element of the power supply circuit is supplying current to an output of the power supply circuit and for determining an indication of a peak current in the magnetic storage element at the end of a charging interval during which the magnetic storage element is storing energy supplied from the power supply circuit; and a control circuit for generating a switching control signal to control a cycle rate of the power supply circuit according to a selectable operating mode of the integrated circuit that is selectable between a buck operating mode and another operating mode, wherein in the buck operating mode the cycle rate is controlled according to a first value computed according to a first algorithm from the indication of the peak current and the detected duration of the flyback interval to maintain the output current at a constant value, and wherein in the another operating mode the cycle rate is controlled according to a second value computed according to a second algorithm from the peak current and the detected duration of the flyback interval to maintain the output current at the constant value, wherein the second algorithm differs from the first algorithm.