JAJSEX5B August   2010  – March 2018 LM3535

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      代表的なアプリケーション
  4. 4 改訂履歴
  5. 5 概要（続き）
  6. 6 Pin Configuration and Functions
    1.     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
    5. 7.5 Electrical Characteristics
    6. 7.6 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 Charge Pump
      2. 8.3.2 Diode Current Sinks
      3. 8.3.3 Ambient Light Sensing (ALS) And Interrupt
      4. 8.3.4 Dynamic Backlight Control Input (PWM Pin)
      5. 8.3.5 LED Forward Voltage Monitoring
      6. 8.3.6 Configurable Gain Transition Delay
      7. 8.3.7 Hardware Enable (HWEN)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown
      2. 8.4.2 Standby
      3. 8.4.3 Active Mode
    5. 8.5 Programming
      1. 8.5.1 I2C Compatible Interface
        1. 8.5.1.1 Data Validity
        2. 8.5.1.2 Start and Stop Conditions
        3. 8.5.1.3 Transferring Data
        4. 8.5.1.4 I2C Compatible Chip Address
        5. 8.5.1.5 Internal Registers of LM3535
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Ambient Light Sensing
          1. 9.2.2.1.1 Ambient Light Sensor Block
          2. 9.2.2.1.2 ALS Operation
            1. 9.2.2.1.2.1 ALS Configuration Example
          3. 9.2.2.1.3 ALS Averaging Time
          4. 9.2.2.1.4 Ambient Light Current Control + PWM
            1. 9.2.2.1.4.1 ALS + PWM Example
        2. 9.2.2.2 LED Configurations
        3. 9.2.2.3 Maximum Output Current, Maximum LED Voltage, Minimum Input Voltage
          1. 9.2.2.3.1 Total Output Current Capability
        4. 9.2.2.4 Parallel Connected and Unused Outputs
        5. 9.2.2.5 Power Efficiency
        6. 9.2.2.6 Power Dissipation
        7. 9.2.2.7 Thermal Protection
        8. 9.2.2.8 Capacitor Selection
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12デバイスおよびドキュメントのサポート
    1. 12.1 ドキュメントの更新通知を受け取る方法
    2. 12.2 コミュニティ・リソース
    3. 12.3 商標
    4. 12.4 静電気放電に関する注意事項
    5. 12.5 Glossary
  13. 13メカニカル、パッケージ、および注文情報

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

8.3.5 LED Forward Voltage Monitoring

The LM3535 has the ability to switch gains (1× or 3/2×) based on the forward voltage of the LED load. This ability to switch gains maximizes efficiency for a given load. Forward voltage monitoring occurs on all diode pins. At higher input voltages, the LM3535 operates in pass mode, allowing the VOUT voltage to track the input voltage. As the input voltage drops, the voltage on the Dxx pins also drops (VDXX = VVOUT – VLEDx). Once any of the active Dxx pins reaches a voltage approximately equal to 130 mV, the charge pump will switch to the gain of 3/2. This switchover ensures that the current through the LEDs never becomes pinched off due to a lack of headroom across the current sinks. Once a gain transition occurs, the LM3535 remains in the gain of 3/2 until an I2C write to the part occurs. At that time, the LM3535 re-evaluates the LED conditions and selects the appropriate gain.

Only active Dxx pins are monitored.