The UCC25710 device is an LLC half-bridge controller for accurate control of multi-string LED backlight applications. It is optimized for multi-transformer, multi-string LED architectures. Superior LED current matching in multiple strings can be achieved with this controller and architecture. Compared to existing LED backlight solutions, the multi-transformer architecture provides the highest overall efficiency from AC input to LED load.

The LLC controller function includes a Voltage Controlled Oscillator (VCO) with programmable FMINand FMAX, half-bridge gate drivers with a fixed dead time of 500 ns and a GM current amplifier. The LLC power delivery is modulated by the controller’s VCO frequency. The VCO has an accurate and programmable frequency range. At very low power levels the VCO frequency goes from FMAXto zero to maximize efficiency at low LED currents.

The LED current loop reference is set by a divider off the VREF 5-V output. The reference can be varied over a 0.5-V to 2.6-V range, allowing analog dimming to be combined with PWM dimming.Read more