| 摘要 |
PROBLEM TO BE SOLVED: To provide a driving circuit of an ultrasonic sensor detecting surely even an object at a short distance by shortening a reverberation vibration time of the ultrasonic sensor. SOLUTION: This driving circuit of the ultrasonic sensor for transmitting an ultrasonic wave by driving intermittently an ultrasonic vibrator, and detecting an object based on a reflected wave signal of the ultrasonic wave from the object is equipped with: a push-pull type transformer 1 having primary winding 1a and secondary winding 1b wherein the ultrasonic vibrator 4 is connected to both ends of the secondary winding 1b; and field effect transistors 2, 3 connected respectively to each end of the primary winding 1a of the transformer 1, to which a transmission driving pulse is applied. The circuit is set so that the electrical resonance frequency by the ultrasonic vibrator 4 and the transformer 1 becomes the same as the mechanical characteristic frequency of the ultrasonic sensor. COPYRIGHT: (C)2005,JPO&NCIPI
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