| 摘要 |
PURPOSE:To transmit a carry signal on a carry signal line at a high speed by setting up the precharging potential of the carry signal line to an intermediate level corresponding to about 1/2 power supply voltage. CONSTITUTION:A transistor (Tr) 10 with 1.5V threshold voltage to be controlled by a precharging clock signal 3 is connected between a 5V power supply 1 and a carry signal line 9 and a TR 16 to be controlled by the clock signal 3 is connected between the signal line 9 and the earth 2. The clock signal 3 and an output of an inverter gate 17a are connected respective gates of the TRs 14a, 14b so that the level of the signal line 9 is pulled up at the 'H' level. Since the signal line 9 is held at 3.5V intermediate level, a carry transmission signal 5 is turned to the 'H' level when the carry signal 4 is turned to the 'H' level, so that a carry transmitting TR 11 is turned on and a signal with an 'L' level is rapidly transmitted through the signal line 9.
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