Quantum mode control for piezoelectric transformers in AC/DC applications

Piezoelectric transformers (PTs) could be an attractive solution to reduce size and weight in AC/DC adapters for portable terminals. In these topologies, the magnetic transformers limit the converter miniaturization and are also EMI sources. Piezoelectric transformers feature low profile high power density and low EMI generation. In this paper, a new control method ("Quantum") for PT-based converters is introduced. As a result, an 8-Watt AC/DC adapter (110 V/sub AC/ input, 12 V/sub DC/ output) is also presented operating at frequencies around 500 kHz with quantum mode control.