Despite contemporary integrated circuit operational amplifiers simplifying linear circuit development, IC fabrication constraints restrict amplifier output strength. Numerous applications, nonetheless, necessitate significantly larger voltage excursions or current (or both) than IC amplifiers can furnish. In these circumstances, an output “enhancer,” or post amplifier, is required to attain the desired voltage or current amplification. Typically, this stage is positioned within the feedback loop of the operational amplifier to preserve the low drift and stable gain properties of the amplifier.
As the enhancer constitutes a gain stage possessing its own inherent AC characteristics, phase shift, oscillation, and frequency response considerations cannot be disregarded if the enhancer and amplifier are to function effectively together. The design of enhancer stages which achieve power amplification while maintaining good dynamic performance presents a complex undertaking. The circuitry for enhancers will vary depending on the application’s specific needs, which can be quite diverse.