Abstract: A piezoelectric transformer signal coupler utilizes a drive circuit including an oscillator constructed to excite the primary of a piezoelectric transformer at its characteristic anti-resonant frequency. Positive feedback signals modulated by the time domain response characteristic of the particular piezoelectric transformer force the oscillator to lock onto its characteristic anti-resonant frequency despite variations thereof due to temperature drift and secondary loading. The resulting drive circuit is implementable as a miniature, low mass integrated circuit mountable on the transformer's piezoceramic wafer to create a signal coupler of a single integrated structure.