SLOSEB6D February   2025  – November 2025 LMH13000

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics for Low-Current Mode, MODE = 0
    6. 5.6 Electrical Characteristics for High-Current Mode, MODE = 1
    7. 5.7 Typical Characteristics
    8. 5.8 Parameter Measurement Information
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Constant Current (ICC)
      2. 6.3.2 Propagation Delay With Temperature
        1. 6.3.2.1 Calibration of Propagation Delay With Temperature
        2. 6.3.2.2 Start Pulse Directly From IOUT
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Optical Time-of-Flight System
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
        3. 7.2.1.3 Application Curve
      2. 7.2.2 Automatic Power-Control Loop Using the LMH13000
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.2.2 Automatic Power-Control Loop Using the LMH13000

For a stable optical power output in laser drive systems, an APC loop maintains constant performance. Fluctuations in temperature, aging effects, and external conditions introduce variations in laser behavior. An APC loop uses optical feedback to dynamically adjust the current through the laser and keep the optical output fixed.

The following schematic supports both dc and pulsed laser operation by using the laser back-facet photodiode.

When the mux operates in high mode, the APC loop closes, and the optical output from the laser LD tunes so that the current picked up by PD converts into a voltage equal to the VSense voltage across the RS resistance. Adjusting the VREF voltage applied to the TLV9001 error amplifier directly controls the optical power. When the mux operates in low mode, the voltage set by the previous APC closed-loop mode stores across C1. This voltage drives the VSET of LMH13000 and fixes the IOUT at the correct level to deliver the required optical power. The user toggles between low and high modes to periodically correct variations in optical output due to external conditions.

For detailed information, see Automatic Power Control for Laser Diodes Using LMH13000

LMH13000 Automatic Power Control Loop Using the LMH13000 in Pulsed Operation Figure 7-5 Automatic Power Control Loop Using the LMH13000 in Pulsed Operation