Q? What is a power booster and when would it be smart to use one?
A!
A power booster is used in tandem with a small signal operational amplifier to provide additional voltage and current gain.
Power boosters are high power current feedback amplifiers designed to create a composite circuit with small-signal “driver” op amps. This type of circuit is intended to extend or “improve” the performance capabilities of a standalone small signal op amp. The resulting composite circuit often provides increases in both voltage and current output capabilities. Looking at the apex power booster series, these devices have a unique topology for setting the gain and the external compensation. When working with power boosters, take care to read the product data sheet for details about the choice of driver amplifier, current limit, supply voltage, voltage gain, and compensation.
Above is an example of a composite amplifier using the Apex PB58. It shows the feedback loop going from the inverting input of the op amp to the output of the power booster. This “overreaching” feedback loop sets the gain for the entire system, while the RGAIN sets the local gain of the power booster. Additionally, the op amp local gain is then the quotient, AOVERALL / ABOOSTER. It’s also possible to operate without a driver amplifier; this results in the highest bandwidth performance at the expense of higher offset voltage.
In addition to boasting high voltage and high current capabilities, the PB series is also fast. The impressive slew rates that power boosters offer is matched or exceeded by only a few expensive or high voltage op amps. If the system requirement is accuracy in the form of low offset, drift, and/or bias current then the PB series, with the proper choice of driver amplifier, can deliver high voltage performance with accuracy equal to the best small-signal op amps available on the market, while doing it economically.
The Apex Microtechnology PB series of power booster amplifiers prove to be a high performance, yet economical and flexible solution to a wide variety of applications
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