ELECTROSTATIC TRANSDUCER, DRIVING CIRCUIT OF CAPACITIVE LOAD, METHOD FOR SETTING CIRCUIT CONSTANT, ULTRASONIC SPEAKER, DISPLAY DEVICE, AND DIRECTIONAL ACOUSTIC SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a driving circuit of an electrostatic transducer capable of driving with low loss while securing a flat output voltage frequency characteristic in a drive frequency band. SOLUTION: The electrostatic transducer 1 (load capacitance) is connected in parallel to a secondary side of an output transformer T as a drive load, and a primary side external resistor R and a coupling capacitor C1 are connected in series to a primary side of the output transformer T. Then, each circuit constant is set so that a resonance frequency f0 of a circuit formed by a self-inductance and the load capacitance of a secondary side winding of the output transformer T is matched or approximately matched to a carrier wave frequency fc of the electrostatic transducer 1. Moreover, each circuit constant is set so that the frequency characteristic of a voltage between terminals of the electrostatic transducer 1 may become the frequency characteristic of a band-pass filter including a drive frequency of the electrostatic transducer 1 in its band-pass filter. COPYRIGHT: (C)2008,JPO&INPIT