voltage regulator

A voltage regulator is used to regulate voltage levels.

Voltage regulator, any electrical or electronic device that maintains the voltage of a power source within acceptable limits.

The voltage regulator is needed to keep voltages within the prescribed range that can be tolerated by the electrical equipment using that voltage.

Types of voltage regulators

Linear voltage regulators
Switching voltage regulators

Linear voltage regulators

Linear voltage regulators are the original type of regulators use to regulate the power supplies.
A linear voltage regulator works like a voltage divider. The resistance of the linear regulator varies with the connected load and input voltage. Therefore, it is able to supply a constant voltage signal.

Types of Linear Voltage Regulators

Shunt
Series

Shunt Regulators

A shunt regulator is used for low-powered circuits. It works by directing the current away from the load and sending it into the ground. It provides a path from the input voltage to a variable resistor which is connected to the ground. It has a very low efficiency but since the wasted current has a very low value, it is neglected.

Applications

Used to absorb current (Sink circuits)
Amplifiers
Voltage power supplies
Electronic circuits that need a precise voltage reference

Series Regulators

The operation of a series voltage regulator is dependent upon the variable component which is connected with the load. When the resistance of the variable component is changed, the voltage drop across the component also changes. Using this technique, the voltage across the load remains the same.
One of the main advantages is that since the variable component and the load are connected in series, the current flowing through them is the same. Thus, the load effectively uses the current. Which makes it more efficient than a shunt regulator.

Switching voltage regulators

series voltage regulator uses a variable element placed in series with the load. By changing the resistance of that series element, the voltage dropped across it can be changed. And, the voltage across the load remains constant.
Switching voltage regulators consist of a series device that is repeatedly switched on and off at a high frequency. The duty cycle is used to control the amount of charge supplied to the load. The duty cycle is controlled by a feedback system that is very similar to the one in the linear regulator. Switching regulators have a high efficiency because the load is either on or off which means it dissipates no energy when it is off.
The switching regulator is superior to the linear regulator when it comes to the output voltage. Because it can supply an output voltage signal which can be greater than the input voltage. Furthermore, it can even generate an opposite polarity voltage signal.

Types of Switching Regulators

Step Up (Boost)
Step Down (Buck)
Step Up/Step Down (Boost/Buck)

Step Up Regulators

Also known as a boost regulator, Step up regulators generate a higher output voltage signal by increasing the input voltage signal. This type of regulator is most commonly used to power multiple LEDs.

Step Down Regulators

Step Down regulators are also called buck regulators. They supply a lower regulated output voltage signal from a higher unregulated input voltage signal.

Step Up/Step Down Regulators

The purpose of this regulator is to increase, decrease or invert the voltage signal. Moreover, it is also called a voltage inverter circuit. Opposite polarity is achieved by the forward and reverse biasing action of the diode. During the off-time, the circuit charges the capacitor and when the capacitor is fully charged, it supplies the opposite polarity output. The efficiency of this type of voltage regulator is very high.

Transistor Voltage Regulators

Zener diodes have a mode due to which it can act as a voltage regulator. This mode is known as the reverse breakdown voltage operation. During this mode, the Zener diode maintains constant output DC voltage signal while the AC ripple voltage signal is completely blocked.

How Does a Voltage Regulator Work?

A voltage regulator is a circuit that creates and maintains a fixed output voltage, irrespective of changes to the input voltage or load conditions.
Voltage regulators keep the voltages from a power supply within a range that is compatible with the other electrical components. While voltage regulators are most commonly used for DC/DC power conversion, some can perform AC/AC or AC/DC power conversion as well. This article will focus on DC/DC voltage regulators.

What are the Basic Parameters for a Voltage Regulator IC?

Some of the basic parameters to consider when using a voltage regulator are the input voltage, output voltage, and output current. These parameters are used to determine which VR topology is compatible with a user’s IC.
Other parameters including quiescent current, switching frequency, thermal resistance, and feedback voltage may be relevant depending on the application.
Quiescent current is important when efficiency during light-load or standby modes is a priority. When considering switching frequency as a parameter, maximizing the switching frequency leads to smaller system solutions.
Additionally, thermal resistance is critical to remove heat from the device and dissipate it across the system. If the controller includes an internal MOSFET, then all losses (conductive and dynamic) are dissipated in the package and must be considered when calculating the maximum temperature of the IC.
Feedback voltage is another important parameter to examine because it determines the lowest output voltage that the voltage regulator can support. It is standard to look at the voltage reference parameters. This limits the lower output voltage, the accuracy of which impacts the accuracy of the output voltage regulation.

Applications of Voltage Regulators

Use in all power supplies to electronic gadgets to regulate voltage and save the device from damage
Used with the alternator of internal combustion engines to regulate the alternator output.
Used for electronics circuits to supply a precise amount of voltage