L4940V5

Abstract

The integrated L4940V5 voltage regulator from STMicroelectronics is a low cost and versatile linear regulator device which gives designers flexibility with its excellent line, load, and temperature stability. This article provides an overview of the L4940V5’s applications and a brief explanation of its working principle.

Introduction

The L4940V5 voltage regulator is an integrated linear regulator manufactured by STMicroelectronics and is a type of voltage regulator which uses an external supply voltage and an internal low-drop series element in order to regulate the output voltage. The L4940V5 is a low cost and versatile device which can be used to provide constant current and voltage output and protects a system from surges and spikes in power supply.

Applications

The L4940V5 is widely used for a diverse range of applications, including:

• Power supplies for consumer electronic products like LEDs, notebooks, mobile phones, and tablets.
• Battery charger applications.
• Two-stage personal computer SMPS (switched mode power supplies).
• Emergency lighting systems.
• External devices like data storage drives.
• Heating elements, temperature sensors, and resistors in industrial applications.

The L4940V5 provides excellent line, load, and temperature stability, making it a popular choice for designers. The device also offers transient protection and constant current limiting, which makes it suitable for industrial applications.

Working Principle

The L4940V5 voltage regulator is a three-terminal device which consists of a reference voltage source, an error amplifier, and a series element. The reference voltage source sets the desired regulated voltage, the error amplifier compares the reference voltage to the output terminal, and the series element controls the current flowing from the supply to the output terminal.

When the input voltage is greater than the desired regulated voltage, the error amplifier causes the series element to reduce its current, thus reducing the output voltage and bringing it to the desired level. Conversely, when the input voltage is less than the desired regulated voltage, the error amplifier causes the series element to increase its current and bring the output voltage back up to the desired level.

The device also features current limiting, which protects the system from excessive current and over heating. When the device reaches its maximum current limit, the series element will stop carrying current and the output voltage will drop until the current drops below the device’s current limit.

Conclusion

The L4940V5 voltage regulator is a versatile device which is suitable for a wide range of applications due to its excellent line, load, and temperature stability. The device also offers current limiting and transient protection, which make it suitable for industrial applications. The device is easy to use and provides a cost-effective and reliable solution for designers.