Integrated on-chip 0.35 μm BiCMOS current-mode DC–DC buck converter

A current-mode DC–DC buck converter with a fully integrated power module is presented in this article. The converter is implemented using BiCMOS technology in amplifier and power MOSFET in a current sensor. The current sensor is realised by the power lateral double-diffused MOSFET with the aspect ratio much larger than that of a matched p-MOSFET. In addition, BiCMOS technology is applied in the error amplifier for an accurate current sensing and a fast transient response. The DC–DC converter is fabricated with 0.35 µm BiCMOS process. Experimental results show that the fully integrated converter operates at 1.3 MHz switching frequency with a supply voltage of 5 V. The output DC voltage is obtained as expected and the output ripple is controlled to be within 2% with a 30 µH off-chip inductor and 100 µF off-chip capacitor.