A 24–20-V Isolated DC-DC Converter Using a Transformer-Based Supply-Generating Technique

This article introduces a 24–20-V isolated dc–dc converter that utilizes a transformer-based supply-generating technique to efficiently drive power transistors. Traditional high-voltage inverters with output voltages above 5 V typically require dedicated power converters, such as LDOs or buck converters, to supply power to gate drivers and control circuits, often leading to reduced efficiency and increased system costs. In this work, an efficient supply-generating technique that directly produces a 5-V power supply from an auxiliary coil—strategically positioned to harness energy from the primary coil—simplifies the power supply design and eliminates the need for external components. The transmitter (TX) and receiver (RX) were fabricated using a 0.18-μm BCD process and packaged in a land grid array (LGA) package. Experimental results confirm that the converter achieves a peak efficiency of 73.2% and a power density of 36.5 mW/mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>. Compared to other integrated solutions, the proposed converter realizes a 13.2% efficiency improvement, and its electromagnetic interference (EMI) performance satisfies the CISPR-32 Class B standard on a two-layer PCB without any stitching capacitors.