摘要
The voltage fluctuations of 48 V batteries in electric vehicles challenge the robustness of switching converters by disturbing the output voltage during cold-crank and load-dump events. To address this issue, this article presents a 48-to-12 V buck converter employing gallium nitride devices to enable high switching frequency ( F SW ) operation and feedforward control, thereby enhancing line transient performance and stabilizing loop dynamics. However, higher F SW also increases the slew rate at the switching node, imposing stricter noise immunity requirements on circuit operation. To overcome this limitation, a noise-immune subnanosecond level shifter is introduced to ensure fast and reliable signal transmission for high-speed operation. In addition, a Miller plateau leakage elimination technique mitigates unintended gate coupling induced by high dV/dt, effectively reducing leakage losses. Beyond high-frequency operation, an adaptive P-type ramp generator facilitates feedforward control by emulating a P-type current mirror, eliminating input-voltage dependency in the control loop. Fabricated using a 0.5-μm GaN process, the proposed converter achieves a peak efficiency of 96.3% while significantly improving transient performance under input-voltage variations.