This paper studies and implements a 15-W driver for piezoelectric actuators. The discussed driver is mainly composed of a flyback converter and a power operational amplifier (P-OPA). The flyback converter produces a variable DC voltage to supply the P-OPA, which outputs an amplified sinusoidal signal with a DC bias of 100V to drive the piezoelectric actuator. The power losses can be reduced because the supply voltage of the P-OPA varies with the peak of the input signal. The power conversion efficiency of the driver can thus be promoted up to more than 30%. From the experimental results, the implemented prototype possesses some advantageous features, such as a nearly constant output-to-input voltage gain, a high slew rate, a high input impedance, a low output impedance, and low output voltage ripples. Copyright (c) 2016 John Wiley & Sons, Ltd.