| 摘要 |
PURPOSE:To accelerate switching speed in horizontal scan by attaching a function of a buffer and that of a horizontal gate switch on an FET of source follower, and making an output circuit into low impedance. CONSTITUTION:All the picture elements of the selected horizontal line of a floating diffusion amplifier FDA 5 are sent to the output circuit 20 via a vertical signal line 9. When switches 17, 18 are turned off and a signal voltage is applied to a capacitor C1 and a switching means 16 is turned on by the horizontal timing pulse phiHn of a horizontal scan circuit 19 in a horizontal blanking period, the output voltage of the capacitor C1 is derived to a signal line 15 via a source follower FET 16. When a horizontal timing pulse phiHn-1 goes to an H level, the FET 16 is operated, and the output voltage of an (n+1)th capacitor C1 is derived to the signal line 15, hereinafter, the same operation is repeated. Thereby, it is possible to accelerate the switching speed by reducing the load capacity and impedance of the output circuit.
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