PROBLEM TO BE SOLVED: To appropriately charge a capacitor for negative pulse generation when generating positive and negative pulses using only the power source of one polarity, in a transmission circuit of an ultrasonic diagnostic apparatus.SOLUTION: When control signals SGS are outputted, as a result of the input side (B point) of a capacitor C2 becoming a ground level, the potential of the output side (A point) becomes -HV. Thus, the negative pulses are generated. After a negative pulse generation period, control signals SG3 are outputted the potential of the input side of the capacitor C2 is returned to +HV and a chargeable state is attained. However, simultaneously with that, when the positive pulses are generated by the output of control signals SG1 and the potential of the B point becomes higher than +HV, the charging of the capacitor C2 becomes impossible by the action of a diode D2. Thus, the control signals SG3 are outputted in the free time in a transmission/reception sequence, and the capacitor C2 is charged using the free time.COPYRIGHT: (C)2011,JPO&INPIT【課題】超音波診断装置の送信回路において、一方極性の電源だけを使って正負パルスを生成する場合に、負パルス生成用コンデンサの充電を適正に行えるようにする。【解決手段】制御信号SGSが出力されると、コンデンサC2の入力側(B点)がグランドレベルとなる結果、その出力側(A点)の電位が-HVとなる。これにより負パルスが生成される。負パルス生成期間後、制御信号SG3が出力され、コンデンサC2の入力側の電位が+HVに戻されて充電可能な状態となる。しかし、それと同時に、制御信号SG1の出力により正パルスが生成されて、B点の電位が+HVよりも高くなると、ダイオードD2の作用によってコンデンサC2の充電を行えなくなる。そこで、送受信シーケンスにおける空き時間において制御信号SG3を出力させ、空き時間を使ってコンデンサC2の充電を行う。【選択図】図1
