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Amplifier With Current Output

IP.com Disclosure Number: IPCOM000073671D
Original Publication Date: 1971-Jan-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Turner, DP: AUTHOR [+2]

Abstract

This amplifier is used to provide power to actuators, such as high performance DC servo motors and DC voice coil linear actuators. This amplifier provides means for both the current control (equivalent to motor torque) and the current limiting requirement in one simple configuration. The amplifier limits power dissipation in the transistors through use of series power resistors while maintaining high motor speed capability and utilizes the same series resistors to drive a circuit for interlocking the positive and negative current amplifiers.

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Amplifier With Current Output

This amplifier is used to provide power to actuators, such as high performance DC servo motors and DC voice coil linear actuators. This amplifier provides means for both the current control (equivalent to motor torque) and the current limiting requirement in one simple configuration. The amplifier limits power dissipation in the transistors through use of series power resistors while maintaining high motor speed capability and utilizes the same series resistors to drive a circuit for interlocking the positive and negative current amplifiers.

Overall current feedback is used to meet the requirement that current and torque be proportional to the input. The current is sensed by feed-back resistor R1 and a voltage proportional or analogous to motor current is returned to the input of the amplifier.

This voltage is compared against the input command e to produce the useful drive to the motor from the power supply. The drive rises or falls until the desired current flows. The opposing or aiding effects from motor inductance, motor resistance, and motor back emf are all minimized by the regulatory action.

Operational amplifier A1 controls the positive current from the positive power supply and operational amplifier A2 controls the negative current from the negative power supply. It is desirable that only one amplifier operate at any particular time. The circuit is designed so that each operational amplifier has the same total gain.

Clamping...