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Circuit for Using Module Pin for Both Input and Output Signals

IP.com Disclosure Number: IPCOM000078073D
Original Publication Date: 1972-Nov-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Minnich, WD: AUTHOR

Abstract

This circuit module has a limited number of pins that connect the circuits of the module to other circuits. The circuit of the drawing is part of a semiconductor device mounted on a module, and it connects a module pin to an input signal receiving circuit and from an output signal producing circuit of the same module. With this arrangement, pairs of circuits share a pin and the module can carry more circuits for the limited number of pins. The circuit also adapts low-power circuits on the module to operate with higher powered external circuits, that are connected to the circuits of the module through the pin.

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Circuit for Using Module Pin for Both Input and Output Signals

This circuit module has a limited number of pins that connect the circuits of the module to other circuits. The circuit of the drawing is part of a semiconductor device mounted on a module, and it connects a module pin to an input signal receiving circuit and from an output signal producing circuit of the same module. With this arrangement, pairs of circuits share a pin and the module can carry more circuits for the limited number of pins. The circuit also adapts low-power circuits on the module to operate with higher powered external circuits, that are connected to the circuits of the module through the pin.

A transistor 2 is connected with a resistor 3 as an emitter-follower to operate four current switches 6, 7, 8 and 9, in response to an output signal at a point 10 from an output producing circuit of the module. The output collector terminals of three of the current switches are connected together at a point 12 to the module pin, to provide a suitably high output current level.

Transistors 14 and 15 are connected as a current switch and cooperate with other transistors to transmit an input signal at point 12, to a point 16 that is connected to a signal receiving circuit of the module, not shown. The connection of the base terminal of transistor 14 to current switch 9 causes transistor 14 to turn on in response to a signal at point 10, to raise the level required at point 12 required for transistor...