Browse Prior Art Database

High Voltage Operational Amplifier

IP.com Disclosure Number: IPCOM000051802D
Original Publication Date: 1981-Mar-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Marple, WP: AUTHOR

Abstract

A high voltage operational amplifier is disclosed which employs a parallel, complementary, emitter-coupled differential amplifier input circuit to drive a complementary, push-pull output circuit.

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High Voltage Operational Amplifier

A high voltage operational amplifier is disclosed which employs a parallel, complementary, emitter-coupled differential amplifier input circuit to drive a complementary, push-pull output circuit.

The input circuit consists of two emitter-coupled differential amplifier circuits, the first comprising the NPN transistors Q1, Q2 and Q5 and the second circuit comprising the PNP transistors Q3, Q4 and Q6. The bases of transistors Q2 and Q4 are connected to a noninverting input terminal, and the bases of transistors Q1 and Q3 are connected to an inverting input terminal. For the noninverting input terminal, a positive pulse will cause Q2 to turn on. When Q2 turns on, Q1 and Q5 turn off. The positive signal on the noninverting input terminal causes Q4 to turn off, thereby causing Q3 and Q6 to turn on. This push-pull operation is transferred through transistors Q11 and Q12, resulting in the NPN transistor Q13 turning on and the PNP transistor Q14 turning off, thereby resulting in a positive output signal for the circuit. Q7-Q10 are biasing transistors. The resultant open- loop voltage gain is approximately 60db, the gain-bandwidth product is approximately 120 MH 2 , and the slew rate for the circuit is approximately 200 volts/microsecond.

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