Browse Prior Art Database

Inverting Open Collector Driver

IP.com Disclosure Number: IPCOM000041678D
Original Publication Date: 1984-Feb-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Favata, AF: AUTHOR [+3]

Abstract

The open collector driver circuit illustrated is capable of sinking a predetermined current magnitude in the down level. When input A is Up, transistor T1 will bias on transistor T2 such that current hogging resistors RH bias T4, T5, and T6 on. A then falls to the Down level. Schottky barrier diode (SBD) S1 level shifts the threshold to provide suitable noise tolerance for the Down-level input. Diodes D1, D2 and D3 clamp the base of T1 to provide suitable noise tolerance for the Up-level input. When input A falls to the Down level, T2 turns off and the bases of T4, T5 and T6 will discharge through S2, S3 and S4. The inhibit/select function is performed via T3. When Z is Up, the base of T1 is down low enough to cut off any input current from T1's emitter. Feedback diode D4 pulls the base of T2 Down.

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Inverting Open Collector Driver

The open collector driver circuit illustrated is capable of sinking a predetermined current magnitude in the down level. When input A is Up, transistor T1 will bias on transistor T2 such that current hogging resistors RH bias T4, T5, and T6 on. A then falls to the Down level. Schottky barrier diode (SBD) S1 level shifts the threshold to provide suitable noise tolerance for the Down-level input. Diodes D1, D2 and D3 clamp the base of T1 to provide suitable noise tolerance for the Up-level input. When input A falls to the Down level, T2 turns off and the bases of T4, T5 and T6 will discharge through S2, S3 and S4. The inhibit/select function is performed via T3. When Z is Up, the base of T1 is down low enough to cut off any input current from T1's emitter. Feedback diode D4 pulls the base of T2 Down. Transistors T4, T5 and T6 are turned off, causing the output to go to the + state (inhibited).

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