Abstract: An integrated circuit is disclosed that integrates a low current, high speed optical receiver with the primary side control functions of the power supply. This is further combined with an optical emitter to create a single component for feedback and control, providing improved performance and manufacturing. A method of providing feedback for the power supply using such an integrated optically coupled control circuit is also disclosed.

Abstract: A circuit for controlling the switching behavior of a field effect transistor (FET) or other power switch in a power supply or converter. The circuit includes an adaptive feedback loop which controls the switching operation of the FET through application of a gate drive signal to the device. The circuit is designed to turn the switching device on or off at the optimum time to reduce the stress and power losses associated with the switching action. The circuit includes a capacitor connected to the FET switch drain to sense the falling voltage across the switch. The adaptive gate drive circuit holds the FET switch off until the drain voltage sensed by the capacitor stops decreasing. At this time, the FET switch voltage is either zero (zero-voltage switching) or has reached the minimum value of its resonant ring (low-voltage switching).

Abstract: In an electronic circuit having an input stage, an output stage having an output voltage, and a feedback element including a coupler having a transmitter coupled to said output stage and a receiver coupled to said input stage, said receiver being galvanically isolated from said transmitter, said transmitter sending an output signal that is a function of said output voltage to said receiver, said receiver generating a receiver output in response to receiving said output signal, a feedback control circuit for said feedback element, said feedback control circuit comprising: a transmitter drive circuit coupled to said transmitter for adjusting said output signal as a function of said output voltage, said transmitter drive circuit comprising an error signal generation stage, said error signal generation stage using a voltage that is a function of the output voltage to generate a feedback control signal, and a non-linear stage, said non-linear stage outputting a transmitter drive signal to said transmitter as a fun