| 摘要 |
PURPOSE:To attain economization and miniaturization, by constituting an A/D converter with comparators operating by single power supply. CONSTITUTION:When a video signal is applied to an input terminal 5, a switch 9 is closed by the time of synchronizing part of the signal and a capacitor 10 is charged with a bias voltage source 8. As a result, the video input signal clamped with a voltage of the bias voltage source 8 and a reference voltage superimposed with the voltage of the bias voltage source 8 are inputted to the comparators 31-3n. Since the bias voltage acts like in-phase to both the inputs, the voltage gives no effect on the comparing operation but gives a bias voltage to the comparators 31-3n. Thus, the comparators 31-3n perform normal comparing operation by connecting a terminal 7 to ground and a positive single power supply to a terminal 6, respectively. |
