PROBLEM TO BE SOLVED: To provide an ultrasonic transducer driving circuit and an ultrasonic diagnostic apparatus, capable of quickly returning the voltage of an output line from the positive or negative voltage to the ground voltage and capable of miniaturizing the circuit size.SOLUTION: Just after the P-side FET (11P) is turned off after turned on according to a P-side transmission signal (PP), the N-side FET (11N) is turned on only for a return period as long as the output line (W) is returned to the ground voltage. Also, just after the N-side FET (11N) is turned off after turned on according to an N-side transmission signal (PN), the P-side FET (11P) is turned on only for the return period as long as the output line (W) is returned to the ground voltage. With this invention, the voltage of the output line (W) can be quickly returned to the ground voltage from the positive voltage (+HV) or the negative voltage (-HV). Since driver circuits (12P and 12N) are logical circuits, the circuit size can be miniaturized compared with an active ground clamp circuit using the FET.COPYRIGHT: (C)2008,JPO&INPIT【課題】超音波振動子への出力ラインの電圧を正電圧または負電圧からグランド電圧に迅速に戻す。回路サイズを小型化する。【解決手段】P側送波信号(PP)に応じてP側FET(11P)をオンしてからオフした直後に出力ライン(W)がグランド電圧に戻る程度の引戻時間だけN側FET(11N)をオンする。また、N側送波信号(PN)に応じてN側FET(11N)をオンしてからオフした直後に出力ライン(W)がグランド電圧に戻る程度の引戻時間だけP側FET(11P)をオンする。【効果】出力ライン(W)の電圧を正電圧(+HV)または負電圧(-HV)からグランド電圧に迅速に戻すことが出来る。ドライバ回路(12P,12N)は論理回路なので、FETを使うアクティブ・グランド・クランプ回路に比べて回路サイズを小型化できる。【選択図】図2
