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Driver Circuit With Dc Feedback

IP.com Disclosure Number: IPCOM000041302D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Favata, AF: AUTHOR [+3]

Abstract

The illustrated driver circuit has a push-pull tri-state output and is capable of sinking a predetermined current magnitude in the Down level. Diode D4 enhances the Down-level output noise tolerance. When input A is Up, T2 conducts. T6 and T7 also conduct, and output A is Down. When input A is Down, T1 conducts. T2, S2, T6 and T7 turn off. As the collector of T2 rises, the Darlington pair T4, T5 pull the output A Up. Diodes D1, D2 and D3 clamp the base of T1 to about 2.4 V. Thus when the output A is Down the base collector junction of T1 does not conduct (saturation). Tri-state operation is accomplished via T3. When Z is Up, T3 conducts. This results in T4, T5 being off. With T3 on, T2 cannot conduct. Also, T6 and T7 cannot conduct.

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Driver Circuit With Dc Feedback

The illustrated driver circuit has a push-pull tri-state output and is capable of sinking a predetermined current magnitude in the Down level. Diode D4 enhances the Down-level output noise tolerance. When input A is Up, T2 conducts. T6 and T7 also conduct, and output A is Down. When input A is Down, T1 conducts. T2, S2, T6 and T7 turn off. As the collector of T2 rises, the Darlington pair T4, T5 pull the output A Up. Diodes D1, D2 and D3 clamp the base of T1 to about 2.4 V. Thus when the output A is Down the base collector junction of T1 does not conduct (saturation). Tri-state operation is accomplished via T3. When Z is Up, T3 conducts. This results in T4, T5 being off. With T3 on, T2 cannot conduct. Also, T6 and T7 cannot conduct.

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