Reference design provides an isolated 48 V output from a wide high-voltage DC input using a half-bridge LLC topology for automotive power systems.
Texas Instruments has developed a 300 W automotive DC-DC converter reference design based on a non-synchronous half-bridge LLC topology. The design provides isolated power conversion for automotive DC-DC converter systems and operates across a wide high-voltage DC input range. It is designed to deliver a regulated 48 V output with a maximum load current of 6.25 A.
The converter operates from an input voltage range of 225 V to 450 V, while the design can continue operating down to 196 V before switching off. The output provides 48 V at up to 6.25 A, delivering a maximum output power of 300 W. The wide input-voltage capability allows the LLC converter to support automotive power systems requiring high-voltage-to-low-voltage isolated DC-DC conversion.
The reference design uses a half-bridge inductor-inductor-capacitor resonant topology. Its resonant switching frequency is nominally 123 kHz and can range from 70 kHz to 222 kHz at full load. The resonant converter architecture is designed to provide efficient power conversion while supporting good dynamic performance and tight load regulation.
Secondary-side regulation is implemented using an automotive-qualified opto-emulator, helping provide regulated output operation without the aging effects associated with conventional optocouplers. The design achieves a full-load efficiency of more than 93.5 per cent, supporting efficient operation in automotive power-conversion applications.
Texas Instruments has tested this reference design and provides resources including a test report, bill of materials, assembly drawing, CAD/CAE files, Gerber files, PCB layout data and schematics. The fully assembled board is intended for testing and performance validation and is not available for sale. Engineers can use these resources to evaluate the half-bridge LLC architecture and develop automotive isolated DC-DC converter systems.
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