SWITCHING MODE POWER SUPPLY USING PIEZOELETRICS DOWN TRANSFORMER

摘要

PURPOSE: A switching mode power supply unit using a piezoelectric transformer is provided to minimize the volume and weight of the switching mode power supply unit by using a transformer without a winding. CONSTITUTION: A rectifier(10) changes an AC voltage to a DC voltage. A switching unit(20) switches the DC voltage to convert the DC voltage into the AC voltage. A switching controller(30) controls the switching frequency of the switching unit. A transformer(40) drops the AC voltage according to the switching frequency. A rectification filter unit(60) converts the dropped AC voltage to DC voltage and smoothes the converted DC voltage. A feedback circuit(70) compares an output voltage with a target voltage. A buffering unit is arranged in lower part of the piezoelectric transformer. The buffering unit prevents damage by the stress of oscillation.