Browse Prior Art Database

Push Pull Driver Using Bipolar and Complementary Metal Oxide Semiconductor Devices

IP.com Disclosure Number: IPCOM000081126D
Original Publication Date: 1974-Apr-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Chin, WB: AUTHOR

Abstract

This is a low-power, high performance push-pull driver circuit featuring a relatively low-power supply voltage output, to drive a highly capacitive load or a terminated transmission line.

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Push Pull Driver Using Bipolar and Complementary Metal Oxide Semiconductor Devices

This is a low-power, high performance push-pull driver circuit featuring a relatively low-power supply voltage output, to drive a highly capacitive load or a terminated transmission line.

Referring to the figure, when the input line is at ground potential, bipolar transistors Q1 and Q3 are turned on. In this event, nodes A and B are clamped at one V(BE) drop above ground potential' Node C is discharged near ground potential and transistor Q2 is off. Since transistor Q3 is on, the output is discharged to slightly above ground.

When the input line is at +Vl, nodes A and B are discharged to ground potential and transistors Q1 and Q3 are off. With Q1 off, Q2 is on, thereby charging the output to a potential of a few hundreds of a millivolt below +V2 where V1 is greater than V2. The inverter circuits P1, N1 and P2, N2 act as a buffer for voltage level shifters. Field effect transistor P3 acts as a nonlinear load to bipolar transistor Q1, thereby minimizing the power dissipation and switching time of Q1.

Schottky diodes D1, D2 and D3 are added to prevent operation in the saturation region. If the circuit is fabricated in a semiconductor substrate the diodes may be eliminated if the substrate is gold-doped or if slight degradation of circuit performance can be tolerated.

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