A new high efficiency and low profile on-board DC/DC converter for digital car audio amplifier is proposed. The proposed converter shows the continuous input current, no DC excitation current of the transformer, the minimized electro-magnetic interference (EMI), no output inductor, and the low voltage stress of the secondary rectifier diodes. The 60W industrial sample of the proposed converter is implemented for digital car audio amplifier and the measured efficiency is 88.3% at nominal input voltage.