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Complementary Output Circuit Using All NPN's

IP.com Disclosure Number: IPCOM000095680D
Original Publication Date: 1964-May-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Berding, AR: AUTHOR

Abstract

The circuit produces an output which is equivalent to a complementary output. The circuit uses transistor s of only one conductivity type.

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Complementary Output Circuit Using All NPN's

The circuit produces an output which is equivalent to a complementary output. The circuit uses transistor s of only one conductivity type.

When any of the three inputs at terminals 10 is down, inverter transistor 12 is held off. Thus, no base current flows to transistor 14 and this transistor is held off by resistor 16. Resistor 18 supplies current to the base of transistor 20, which causes transistor 20 to saturate, thus driving the output at terminal 22 almost to V2. When the inputs to all the terminals 10 are positive, the current through resistor 24 turns on transistor 12.

This action causes transistor 20 to turn off, since current is no longer supplied by resistor 18. Transistor 14 then conducts because of the current supplied to the base. When transistor 14 turns on, it pulls the output at terminal 22 down almost to ground potential. Thus, the performance of the circuit is equivalent to the output of a complementary NPN-PNP pair. The circuit uses only NPN transistors.

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