Texas Instruments has developed a digitally controlled 1 kW LLC reference design for server power supplies requiring high-speed load-transient response and a 12 V output.
Texas Instruments has released a 1 kW isolated power-supply reference design based on a half-bridge LLC topology. The design accepts a 340 V to 420 V DC input and provides a nominal 12 V output at up to 84 A, delivering 1008 W 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 8 kHz and is designed for high load-transient performance. Under a 0% to 100% load transition at 2.5 A/µs, the output deviation remains below 500 mV peak-to-peak. For a 0% to 150% load transition at the same slew rate, the deviation remains below 800 mV 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 100 kHz resonant frequency, 12 V output and an output-current range of 0 A to 84 A. 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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