Analog Electronics III

Analog Electronics III

During the course of Analog Electronics I began the study of a basic operational amplifier that introduced simple amplifier stages. Later, in the course of Analog Electronics II, the input stage was analyzed with the presentation of the differential pair. So, Analog Electronics III becomes the culmination of the description of a simple op amp with the study of the output stages, which are related to the drive or power. These steps are particularly important in the amplification of audio signals.

During the description of the operational amplifiers in Analog Electronics II, emphasis was placed on the need for a very high open loop gain in order to ensure that the closed loop gain could be controlled by the values of the external components to the core amplifier. The closed loop gain is obtained when feedback is applied to the system, which; while it reduces the overall gain of the amplifier, provides improvements in other characteristics such as frequency response and robustness with respect to variations in the internal circuit parameters. The complete analysis of a feedback configuration can be complex and therefore techniques that facilitate this task and thus exposed, drawing conclusions and / or design criteria.

An improvement in the operation of the amplifiers using feedback is achieved through the use of an error signal when input and output forming negative feedback system compares.

The use of negative feedback amplifiers not only used to amplify the signal of interest, trying at all times to maintain the linearity of processing. While manipulating the signal required maintaining the information contained therein, it is sometimes necessary to remove some signal components, an application specific interference can become and thus provide no information desired. By using specific configurations involving amplifiers they can use the frequency response of systems to create blocks called processing filters that perform the work of debugging information of interest. This course introduces the types of filters, the design process of the same high level and then develops some basic architecture.

Finally, in terms of comparison of signals at the input of a feedback system, if the comparison between the signals involved regeneration firing produces the values of the output signal, a behavior of positive feedback which is obtained is not suitable for use in amplifiers. However, there are alternative configurations amplifiers imposed this type of feedback, and in this category the comparators and oscillators are included.

Course Learning Outcomes

After completing the course the student will be able to know the full configuration of a basic operational amplifier operation and understand their behavior from negative feedback and use in applications. Therefore the student will be able to identify potential applications of positive feedback and quality measures oscillators.