1kW Digital LLC Power Supply

Texas Instruments has developed a digitally controlled 1kW LLC reference design for server power supplies requiring high-speed load-transient response and a 12V output.

Texas Instruments has released a 1kW isolated power-supply reference design based on a half-bridge inductor-inductor-capacitor (LLC) topology. The design accepts a 340V to 420V DC input and provides a nominal 12V output at up to 84A, delivering 1008W of output power. It targets server power supplies and data-centre applications.

The reference design uses digital hybrid hysteretic control (HHC) through a digital controller. It achieves a peak loop bandwidth of 8kHz and is designed for high load-transient performance. Under a 0 to 100 per cent load transition at 2.5A/µs, the output deviation remains below 500mV peak-to-peak. For a 0 to 150 per cent load transition at the same slew rate, the deviation remains below 800mV peak-to-peak.

The design also supports monotonic startup under different load conditions and burst mode for reducing power consumption at light loads. Secondary-side synchronous-rectification control is integrated into the design, while configurable dead time provides additional control over switching operation. The reference design also includes low audio susceptibility to suppress the effect of input-voltage ripple.

The test report specifies a 100kHz resonant frequency, 12V output, and an output-current range of 0A to 84A. The reference design board measures 175 mm × 116 mm × 42 mm. TI notes that additional cooling airflow may be used during testing to reduce the temperature of the power board.

Texas Instruments provides supporting resources for the reference design, including a test report, assembly drawing, bill of materials (BOM), computer-aided design and engineering (CAD/CAE) files, Gerber files, PCB layout, and schematic. The fully assembled board is intended for testing and performance validation and is not available for sale. 

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