LM317

LM317 Voltage Regulator Overview

Key Features:

• Adjustable Output: The LM317 can provide an adjustable output voltage ranging from 1.25V to 37V.
• Output Current: It can supply current up to 1.5A, although heatsinking may be required for higher currents.
• Line Regulation: Typically around 0.01% per volt change in input voltage.
• Load Regulation: Typically around 0.1% per ampere change in load current.
• Adjustable Output Voltage: The output voltage is set using two external resistors connected to the ADJ (adjust) pin.
• Internal Thermal Overload Protection: The LM317 includes internal thermal overload protection and current limiting to prevent damage under fault conditions.

Pin Configuration:

• Pin 1 (Adjust): Connected to resistors to set the output voltage.
• Pin 2 (Output): Provides the regulated output voltage.
• Pin 3 (Input): Connected to the unregulated voltage source (typically 3V to 40V).

Typical Applications:

• Adjustable Power Supply: Used to create adjustable voltage power supplies for various electronics projects.
• Battery Chargers: Can be used in battery charging circuits to regulate the charging voltage.
• Constant Current Source: When used with an external resistor, the LM317 can also function as a constant current source.

Advantages:

• Versatility: Can be configured for a wide range of output voltages.
• Reliability: Known for its stable performance and built-in protection features.
• Ease of Use: Requires minimal external components for basic operation.

Disadvantages:

• Heat Dissipation: May require heatsinking, especially when supplying higher currents or voltage differentials.
• Power Loss: Can dissipate significant power as heat when operating at high currents or large voltage drops.