| 摘要 |
PURPOSE:To keep an intermediate level to a prescribed level stably with high accuracy even when a characteristic variation due to power supply fluctuation or temperature change of a diode by clamping a low level of a multi-value level of three or more values. CONSTITUTION:A negative bias drive circuit 1 outputting a pulse having an amplitude in response to a power voltage and fed with a negative bias power supply and a drive circuit 2 whose power is supplied from the negative bias power supply via the 1st diode 4 and outputting a clock pulse having a level between a low level and an intermediate level to be stabilized at least are provided. Then the 2nd diode 6 clamping a high level of the output pulse from the negative bias drive circuit 1, a rectifying smoothing circuit using the 3rd diode 7 to rectify the output pulse subject to high level clamp, smoothing it by a capacitor 8 and obtaining a negative bias DC output and the 4th diode 9 clamping the low level of the clock pulse to the negative bias DC output level are provided. |
