SNVS774Q May   2004  – June 2020 LM117 , LM317-N

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     Typical Application
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions, Metal Can Packages
    2.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information, LM117
    5. 7.5 Thermal Information, LM317-N
    6. 7.6 LM117 Electrical Characteristics
    7. 7.7 LM317-N Electrical Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Load Regulation
    4. 8.4 Device Functional Modes
      1. 8.4.1 External Capacitors
      2. 8.4.2 Protection Diodes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1  1.25-V to 25-V Adjustable Regulator
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curve
      2. 9.2.2  5-V Logic Regulator With Electronic Shutdown
      3. 9.2.3  Slow Turnon 15-V Regulator
      4. 9.2.4  Adjustable Regulator With Improved Ripple Rejection
      5. 9.2.5  High Stability 10-V Regulator
      6. 9.2.6  High-Current Adjustable Regulator
      7. 9.2.7  Emitter-Follower Current Amplifier
      8. 9.2.8  1-A Current Regulator
      9. 9.2.9  Common-Emitter Amplifier
      10. 9.2.10 Low-Cost 3-A Switching Regulator
      11. 9.2.11 Current-Limited Voltage Regulator
      12. 9.2.12 Adjusting Multiple On-Card Regulators With Single Control
      13. 9.2.13 AC Voltage Regulator
      14. 9.2.14 12-V Battery Charger
      15. 9.2.15 Adjustable 4-A Regulator
      16. 9.2.16 Current-Limited 6-V Charger
      17. 9.2.17 Digitally Selected Outputs
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Thermal Considerations
        1. 11.1.1.1 Heatsink Requirements
        2. 11.1.1.2 Heatsinking Surface Mount Packages
          1. 11.1.1.2.1 Heatsinking the SOT-223 (DCY) Package
          2. 11.1.1.2.2 Heatsinking the TO-263 (KTT) Package
          3. 11.1.1.2.3 Heatsinking the TO-252 (NDP) Package
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Related Links
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.2.14 12-V Battery Charger

The LM317-N can be used in a battery charger application shown in Figure 32, where the device maintains either constant voltage or constant current mode depending on the current charge of the battery. To do this, the part senses the voltage drop across the battery and delivers the maximum charging current necessary to charge the battery. When the battery charge is low, there exists a voltage drop across the sense resistor RS, providing constant current to the battery at that instant. As the battery approaches full charge, the potential drop across RS approaches zero, reducing the current and maintaining the fixed voltage of the battery.

LM117 LM317-N 906326.gif

LM117 LM317-N 906353.gif
Use of RS allows low charging rates with fully charged battery.
Figure 32. 12-V Battery Charger