A voltage regulator
is one of the most widely used electronic circuitry in any device. A
regulated voltage (without fluctuations & noise levels) is very
important for the smooth functioning of many digital electronic devices.
A common case is with micro controllers, where a smooth regulated input
voltage must be supplied for the micro controller to function smoothly.
You may also like this article on Regulated Power Supply
Voltage regulators are of different
types. In this article, our interest is only with IC based voltage
regulator. An example of IC based voltage regulator available in market
is the popular 7805 IC which regulates the output voltage at 5 volts.
Now lets come to the basic definition of an IC voltage regulator. It is
an integrated circuit whose basic purpose is to regulate the unregulated
input voltage (definitely over a predefined range) and provide with a
constant, regulated output voltage.
An IC based voltage regulator can be
classified in different ways. A common type of classification is 3
terminal voltage regulator and 5 or multi terminal voltage regulator.
Another popular way of classifying IC voltage regulators is by
identifying them as linear voltage regulator & switching voltage
regulator. There is a third set of classification as 1) Fixed voltage
regulators (positive & negative) 2) Adjustable voltage regulators
(positive & negative) and finally 3) Switching regulators. In the
third classification, fixed & adjustable regulators are basically
versions of linear voltage regulators.
Block Diagram of 3 Terminal IC based Voltage Regulator
We have given below the block diagram of a 3 terminal IC based voltage regulator.
