This isolated open-loop LLC transformer driver converter provides dual +20-V and -4-V outputs up to 6 W for traction inverter applications. The LLC topology allows the transformer to have significant leakage inductance, but a much smaller primary-secondary capacitance, which significantly reduces common-mode current injection through the bias transformer. This reference design offers a high level of integration and high efficiency in a compact form factor.
Features
- Open-loop architecture eliminates secondary feedback resulting in a compact size
- LLC topology utilizes the transformer's leakage inductance allowing small secondary side resonant capacitors
- Secondary-side resonance is less sensitive to external component tolerances
- High efficiency (85% at 50% loading)
- Excellent total output voltage regulation