Improved high-voltage push-pull amplifier using DMOS power fets

A bridge-type push-pull amplifier using a DMOS power FET pair, differentially driven by a dual operational amplifier phase splitter, to provide an AC high-voltage floating output is investigated, particularly for electro-optic or capacitive loads. The amplifier exploits the advantages of the above MOSFETs and uses an appropriate feedback circuitry and class A low-current biasing to improve its linearity, thermal stability, bandwidth capabilities, and some mismatch-effect features. A practical circuit implementation is also presented which gives up to 780 V peak-to-peak output with an overall voltage gain of 430 and a maximum gain-bandwidth product of about 2.9 GHz for the entire system. Testing results in general verify the majority of theoretical expectations.