A low-profile low-power converter with isolated voltage output

In this paper, an isolated low-profile power converter using a coreless printed-circuit-board (PCB) transformer is described. The diameter of the coreless PCB transformer is merely 0.46 cm. Because of the high frequency (8 MHz) operation involved, the gate drive electronics has to be soft-switched in order to achieve high energy efficiency and reduce the gate drive power consumption. The very thin PCB used in the converter facilitates energy coupling from the primary winding to the secondary side of the transformer. The output voltage can be regulated and programmable. The converter's power output is about 0.5 W with a typical transformer efficiency of 63%.