Monolithic Power Systems, Inc.
Energy recycle circuit for flyback circuit and method thereof

Abstract:

An energy recycle circuit for a flyback circuit, the flyback circuit has a primary winding of a transformer a primary switch. The energy recycle circuit has an energy recycle branch coupled in parallel with the primary winding, and an integrated circuit having a plurality of pins. The energy recycle branch has an auxiliary switch and a clamp capacitor connected in series. Among the plurality of pins, a first pin receives an external supply voltage. A second pin is used as a power ground that is different from a primary power ground. A third pin is used to sense a branch current flowing through the energy recycle branch. A fourth pin is used to control an operation of the auxiliary switch. A fifth pin that is connected to an external resistor for setting a maximum ON-time threshold of the auxiliary switch.