Basic Series Regulator Circuit Design of Op Amp


The series regulator derives its name from its control element. The output voltage. VO, is regulated by modulating an active series element, usually a transistor that functions as a variable resistor. Changes in the input voltage. VI, will result in a change in the equivalent resistance of the series element identified as RS. The product of the resistance. RS, and the load current. IL creates a changing input-to-output differential voltage, VI – VO, that compensates for the changing input voltage. The basic series regulator is illustrated in Figure 5-3, and the equations describing its performance are listed below.

Figure 5-3. Basic Series Regulator

Series regulators provide a simple, inexpensive way to obtain a source of regulated voltage. In high-current applications. However, the voltage drop which is maintained across the control element will result in substantial power loss and a much lower efficiency regulator.