High-density, zero-voltage switching (ZVS) flyback controller with integrated SR control

The UCC28781 is a zero-voltage-switching (ZVS) controller which can be used at

very high switching frequencies to minimize the size of the transformer and enable

high power density.

With direct synchronous rectifier (SR)

control, the controller does not need a separate SR controller, as it can drive the

SR FET directly to maximize efficiency and simplify design. (For isolated

applications, an isolated gate-driver IC is required.)

Using adaptive dead-time control for

ZVS, switching losses and EMI are minimized. This design results in a controller

with extremely high conversion efficiency across the entire operating range.

The programmable adaptive burst mode

(ABM) gives flexibility to control when the controller enters and exits standby mode

to optimize standby power in light and no-load conditions. ABM also helps to reduce

ripple and minimize audible noise.

The controller offers multiple

protection modes with automatic restart (retry) responses.