This reference design employs LM5155 Boost/Flyback/SEPIC controller to provide 6-W outputs with dual-output SEPIC topology. The input is 12-VDC: and outputs are ±60 V/50 mA. The switching frequency is set at 500k Hz. This design achieves 88.2% peak efficiency. The cross regulation of -60-V rail is within ±4% at the total load range. External voltage control pin is optional to regulate output voltage from 0~60 V. The high efficiency and small PCB dimensions (25mm*14mm*4.5mm) make the design suitable for portable ultrasound probe application.