K04RLM12 Datasheet, PDF (15/23 Pages) Texas Instruments – Operational Amplifier

OBSOLETE
K04RLM12, LM12CL
www.ti.com
SNOSBY8D – MAY 1999 – REVISED APRIL 2013
SERVO AMPLIFIERS
When making servo systems with a power op amp, there is a temptation to use it for frequency shaping to
stabilize the servo loop. Sometimes this works; other times there are better ways; and occasionally it just doesn't
fly. Usually it's a matter of how quickly and to what accuracy the servo must stabilize.
This motor/tachometer servo gives an output speed proportional to input voltage. A low-level op amp is used for
frequency shaping while the power op amp provides current drive to the motor. Current drive eliminates loop
phase shift due to motor inductance and makes high-performance servos easier to stabilize.
This position servo uses an op amp to develop the rate signal electrically instead of using a tachometer. In high-
performance servos, rate signals must be developed with large error signals well beyond saturation of the motor
drive. Using a separate op amp with a feedback clamp allows the rate signal to be developed properly with
position errors more than an order of magnitude beyond the loop-saturation level as long as the photodiode
sensors are positioned with this in mind.
VOLTAGE REGULATORS
An op amp can be used as a positive or negative regulator. Unlike most regulators, it can sink current to absorb
energy dumped back into the output. This positive regulator has a 0–50V output range.
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: K04RLM12 LM12CL
Submit Documentation Feedback
15