| 摘要 |
PURPOSE:To avoid the yield and the breakdown of an output transistor TR by halving the reverse bias caused between the base and the emitter of the output TR. CONSTITUTION:A 3rd npn-type output TR 27 includes a collector connected to the output X with an emitter and a base connected to a lower potential power supply Vss and a node N2 respectively. A forcible setting means 10 forcibly sets the 1st and 2nd nodes N1 and N2 at low levels in response to a prescribed control signal C. In such a constitution of an output buffer, the 1st-3rd output TR (25, 26 and 27) are all turned off. Furthermore, a cutting means 42 is added to the output buffer to cut the connection secured between the emitter of the TR 25 and the power supply Vss while both nodes N1 and N2 are kept at low levels. |
