초록 ▼

An AC/DC converter of the present invention includes a transformer implemented by a piezoelectric transformer. Power fed from a commercially available power source (14) is converted to a DC voltage by rectification and smoothing. The DC voltage is transformed to a high frequency (about 100 kHz) puls

An AC/DC converter of the present invention includes a transformer implemented by a piezoelectric transformer. Power fed from a commercially available power source (14) is converted to a DC voltage by rectification and smoothing. The DC voltage is transformed to a high frequency (about 100 kHz) pulse voltage by switching FETs (Field Effect Transistors) (5) and (6). The pulse voltage is applied to the input of a piezoelectric transformer (9). The transformer (9) has its vibration mode and dimension selected such that the resonance frequency of the transformer is substantially identical with the frequency of the above pulse wave. A high frequency AC voltage is produced from the output side of the transformer (9). The AC voltage is transformed to a DC voltage by rectification and smoothing and then fed to a load resistor (13). The piezoelectric transformer is easy to miniaturize, compared to an electromagnetic transformer. The entire AC/DC converter can therefore be reduced in size.

대표청구항 ▼

[ What is claimed is:] [1.] A switching regulator type AC/DC step-down voltage converter for converting a commercial AC power source to a DC power source, comprising an input circuit for converting the AC power source to an input signal to a step-down piezoelectric transformer, and an output circuit

[ What is claimed is:] [1.] A switching regulator type AC/DC step-down voltage converter for converting a commercial AC power source to a DC power source, comprising an input circuit for converting the AC power source to an input signal to a step-down piezoelectric transformer, and an output circuit for converting the piezoelectric transformer output signal to a substantially DC power supply, wherein said piezoelectric transformer includes an input section and an output section, each being implemented as a plurality of electrodes laminated in a lengthwise direction of said piezoelectric transformer and connected in parallel with each other, and wherein portions between said plurality of electrodes are polarized in the lengthwise direction, whereby said piezoelectric transformer is operable in a longitudinal vibration mode.