Step-down piezoelectric transformer fabricated with (1-x)Pb(Mg(1/3)Nb(2/3))O3-xPbTiO3 single crystal

In present work, a ring-type unipoled step-down piezoelectric transformer with the dimensions of Phi16x0.7 mm(3) was designed and fabricated using relaxor ferroelectric single crystal (1-x)Pb(Mg(1/3)Nb(2/3))O(3)-xPbTiO(3) (PMN-PT). Both the input and output parts of this transformer were poled along the thickness direction, utilizing the radial vibration mode of PMN-PT. The electrical measurement results indicated that under the matching load resistance of 257 Omega, a voltage transformation ratio of 0.44 was obtained at the resonance frequency of 105 kHz. The frequency and load dependences of this transformer were also systematically studied and discussed. With the input voltage increasing, a maximum output power of about 0.9 W was obtained with the temperature rise less than 5 degrees C. This step-down single-crystal transformer show potential applications in compact-size, small-power ac-dc converters.