This paper describes the design of a high-voltage amplifier for a piezoelectric transducer used in underwater communication applications, which incorporates boosting and signal generation within a single boost converter stage improving the total efficiency of the system. The proposed architecture combines hysteretic ripple current-mode control with an adaptive soft switching technique to achieve improved power efficiency over the full output power range. This is achieved by dynamically controlling the inductor current ripple to keep the converter running in soft switching. The feedback control and the soft switching regulation are implemented in a 0:25 μm 60V TSMC process with an external power stage. The system achieves a peak efficiency of 85% at 20W of output power up to 30kHz signal frequency.