| 摘要 |
PURPOSE:To prevent a tri-state logical circuit from being damaged because of bus fight by providing a suppressing potential generating means transmitting and holding a suppressing potential to a state control input terminal of a tri- state logical circuit. CONSTITUTION:When a voltage VCC is increased from a zero potential attended with application of power and reaches a collector-emitter voltage of a transistor (TR) TR3, since a system set signal is a zero potential before application, the voltage is applied to a base of the TR3 via a resistor R3, the R3 is turned on and a collector potential of the TR3 is suppressed to zero potential. The TR1, TR2 are both turned off attended with the operation and this state is maintained. |
