In electrical engineering, a linear voltage regulator is a system that is utilized in maintaining a steady voltage. The regulator's resistance varies according to the load as well as the input voltage, leading output of unchanged voltage. This regulating device is constructed in such a manner that it behaves like a variable resistor which adjusts a voltage divider network continuously to keep up a steady yield voltage. In contrast to this, a switching regulator takes the help of active equipment that turns ON/OFF to keep an average output value. Since the regulated voltage should always be lower than the output voltage, the value of efficiency is limited. To enable the active device to drop some voltage, the input voltage needs to be high.
Linear regulators may keep the regulating device in between the regulated load and the source (series) or in parallel with the load. Simple linear regulators may include a series of resistors and a Zener diode while the complex ones come with power pass element, voltage reference, and error amplifiers. Since a linear regulator is one of the most common elements in several devices, ICs are very common. Linear voltage regulators may also be constructed by several vacuum tubes or solid-state components.
There are 2 basic forms of Linear Voltage Regulators. One is the series regulators and the other one is the shunt regulators. Most of the linear regulators in use are marked with maximum rated output current. This is commonly limited by the current conveying ability, or by the power dissipation ability of the output transistor.
- Series Regulators – Series regulators are the most commonly used regulators; they are much more efficient than the shunt regulators. This regulator works by setting up a path from the load to the supply voltage through a variable resistance (transistor). For this reason, it is commonly known as pass transistor. The amount of power dissipated by the regulator is equal to the product of the voltage drop with the power supply output current in the device. For the reduced stress and efficiency on the pass transistor, manufacturers generally try to decrease the amount of voltage drop. It is found that not all the circuits are regulated efficiently as soon as their input voltage comes near the required output voltage. Those that are regulated efficiently is known as Low Dropout regulators.
- Shunt Regulators – This regulator works by giving a way from the ground to the supply voltage through a variable resistance. The current coming from the regulator is made to flow to the ground by diverting away from the load. Because of this reason, the shunt regulators are less efficient than the series regulator. These kinds of regulators are used in very low-powered circuits where the squandered current is too little to even think about being of concern.
This was all we have regarding linear voltage regulators. Hope you liked going through it. Brands that manufacture these regulators are ON Semiconductor, Texas Instruments, and STMicroelectronics. Make sure to check them out using the links as provided.