The effect of environmental temperature on the performance of piezoelectric transformer

Abstract

Over the years, piezoelectric transformer (PT) was used in inverters to drive cold cathode fluorescent lamps (CCFL). As it stands now, CCFL still was considered to be the primary light source for the backlight module of LCD TVs. It is know that transformers play important role in backlight module performance. Since the LCD TV might be sold to different parts of the world and the inverters as well as the power boards do produce heat, the piezoelectric transformers are expected to perform well in vastly different environmental temperatures. Since temperature will influence the material properties, the resonant frequency of piezoelectric transformer gets affected easily by the environmental temperature. In this paper, we operated the Rosen-type piezoelectric transformers of various thicknesses in temperatures such as 25, 50, 70, and 90℃ to examine the temperature dependency of the resonant frequency, the power efficiency, the step-up ratio, and the output current with CCFL as the loads. Simulation was also done to study the trend of resonant frequency variations in different temperatures. Furthermore, the effect of environmental temperature to the performance of various thicknesses of Rosen-type PT was examined. The relationship between the CCFL used and the operating temperature was investigated with an attempt to explore future applications.