There are maximum integrated IC’s that need a constant voltage with which they could operate. They have their voltage regulator no matter whether it is a simple Logic Gate or a complex microprocessor. The most common operating voltages are 5V, 12V, and 3.3V.To act as a voltage source we have batteries and DC Adaptors as the maximum time to our circuit design they cannot be directly connected since the voltage from them is not regulated.
A voltage regulator is a beefed-up emitter follower. A transistor a stable reference is connected that spits out a constant voltage, dropping the remaining.
They even consist of a built-in error amplifier, which samples the output voltage (again through a divider), then with the reference voltage it is compared, the difference is calculated, and accordingly drives the output transistor. From voltage divider, this is far different, which through just a magnitude smaller faithfully replicates the input signal.
Limitations of Voltage Regulator
The simplicity of linear regulators is the biggest advantage; nothing else is needed.
However, they are available with their own set of limitations.
The working of the linear voltage regulator is associated with a variable resistor that provides feedback, dropping any unneeded voltage. Into heat this wasted energy is converted, making the power regulator hot and inefficient at high currents.
For example, a power loss of (12V – 5V)*1A is seen with a 5V regulator with a 12V input running at 1A, which is 7W. This says there is a lot of wasted energy, and the efficiency is only 58%.
So, at differentials of high input-output voltage or high currents, regulators have pathetic energy efficiency.
With the use of more than one regulator in series with decreasing output voltages (up to the desired voltage value) the input-output differential voltage problem can be overcome so that in steps the voltage is dropped. The overall power dissipation is equivalent to having one automatic voltage regulator across all the devices the heat load is spread out along with decreasing overall operating temperature.
By
using a switching supply the power and efficiency limitations can be overcome,
but the choice is application dependent. Follow us on Twitter
