The present invention includes a digital controller for use with an ultrasound power amplifier circuit to increase linearity and efficiency of the ultrasound power amplifier circuit. The digital controller includes a digital signal generator and a memory unit that is coupled to the digital signal generator. The memory unit includes a processor that obtains an output signal from the ultrasound power amplifier circuit, calculates error by obtaining a difference between an ideal output signal and the output signal that is obtained from the ultrasound power amplifier circuit, and equalizes an input signal from the digital signal generator to reduce nonlinearity in the output signal of the ultrasound power amplifier circuit. The memory unit includes a look-up-table for storing values of error.