| 摘要 |
The current mode bus driver which is disclosed couples input digital signals to a bus which is normally biased with a voltage difference representing one binary type. The current mode bus driver responds to input digital signals of the other binary type by connecting a current source to one lead of the bus and a current sink to the other lead of the bus, thereby driving the bus to a voltage difference which represents the other binary type. In response to input digital signals of the first-mentioned binary type, the bus driver isolates the current source and current sink from the bus and connects the current source directly to the current sink. The selective switching is performed by n-channel MOSFETs which are driven by the input digital signals through unique buffer driver circuits employing a CMOS inverter, an n-channel MOSFET and an NPN transistor. A combination of MOSFETs and NPN transistors provide a current source and sink that permit operation of the bus at very low voltage levels. |
