SNVSCQ2A March   2025  – August 2025 LP5817

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Timing Diagrams
    8. 6.8 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Analog Dimming
      2. 7.3.2 PWM Dimming
      3. 7.3.3 Sloper
      4. 7.3.4 Protections
        1. 7.3.4.1 UVLO
        2. 7.3.4.2 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Initialization Mode
      2. 7.4.2 Standby and Normal Mode
      3. 7.4.3 Shutdown Mode
      4. 7.4.4 Thermal Shutdown Mode
    5. 7.5 Programming
      1. 7.5.1 I2C Data Tansactions
      2. 7.5.2 I2C Data Format
      3. 7.5.3 Command Description
    6. 7.6 Register Maps
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Application
      2. 8.2.2 Design Parameters
      3. 8.2.3 Detailed Design Procedure
        1. 8.2.3.1 Program Procedure
        2. 8.2.3.2 Programming Example
      4. 8.2.4 Application Performance Plots
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.3.1 Analog Dimming

There are two methods to control the current gain of each output channel.

  • Global 1-bit Maximum Current (MC) control for all channels without external resistor
  • Individual 8-bit Dot Current (DC) control for each channel

The maximum output current IOUT_max of each channel can be programmed by the 1 bit MAX_CURRENT. When the device is powered on, the default value of MC is 0h, which is 25.5mA.

Table 7-1 Maximum Current (MC) Bit Setting
1-bit Maximum Current (MC)IOUT_MAX (mA)
BinaryDecimal
0 (default)0 (default)25.5 (default)
1151

The LP5817 can individually adjust the analog output current of each channel by using Dot Current (DC) function. The brightness deviation among the LED bins can be miminized to achieve uniform display performance through the DC setting. The DC is programmed in an 8-bit depth, so the analog current can be adjusted with 256 steps from 0 to 100% of IOUT_MAX.. The default value of all DC is 0h, which is not current output.

Table 7-2 Dot Current (DC) Bits Setting
8-bits Dot Current (DC) RegisterRatio of IOUT_MAX
BinaryDecimal
0000 0000 (default)0 (default)0% (default)
0000 000110.39%
0000 001020.78%
---------
1000 000012850.2%
---------
1111 110125399.2%
1111 111025499.6%
1111 1111255100%

By configuring the MC and DC, the analog output current of each channel can be calculated as Equation 1:

Equation 1. I O U T   ( m A ) = I O U T _ M A X × D C 255

The average output current of each channel can be caculated asEquation 2:

Equation 2. I A V E   ( m A ) = I O U T _ M A X × D C 255 × D P W M

  • DPWM is the PWM duty.