| 摘要 |
PURPOSE:To attain a circuit suitable for circuit integration by making a gate of a thyristor of load side as a control terminal in a switching for a high frequency voltage signal driving an ultrasonic wave vibrator with the thyristor so as to reduce crosstalk and lower the control voltage. CONSTITUTION:When a negative voltage -VG is impressed to an N gate 41 of the thyristor 1, the thyristor 1 is turned on and a signal VIN inputted to the cathode 3 is fed to a load 5 and a high frequency voltage VA is generated to the anode 2. When a positive voltage +VG is fed to the gate 41 convsrsely, the thyristor 1 is turned off, even if a signal voltage having a negatie peak value -VPP is impressed, the thyristor is blocked by the J2 junction of the thyristor 1 and a potential of the gate 41 is kept to the +VG and no gate current conducting the thyristor flows. Then even if a gate current flows to a positive peak value +VPP via a junction capacitance, the current flowing to the anode 2 is neglected because of the difference in the amplification factor of PNP, NPN transistors constituting the thyristor 1 and the crosstalk at the turning-off of the thyristor 1 is reduced. |
