SNVS867 June   2014 LM3633

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 Handling 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 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Control Bank Mapping
        1. 7.3.1.1 High-Voltage Control Banks (A and B)
        2. 7.3.1.2 Low-Voltage Control Banks (C, D, E, F, G, and H)
      2. 7.3.2 Pattern Generator
      3. 7.3.3 PWM Input
      4. 7.3.4 HWEN Input
      5. 7.3.5 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 High-Voltage LED Control
        1. 7.4.1.1  High-Voltage Boost Converter
        2. 7.4.1.2  High-Voltage Current Sinks (HVLED1, HVLED2 and HVLED3)
        3. 7.4.1.3  High-Voltage Current String Biasing
        4. 7.4.1.4  Boost Switching-Frequency Select
        5. 7.4.1.5  Automatic Switching Frequency Shift
        6. 7.4.1.6  Brightness Register Current Control
          1. 7.4.1.6.1 8-Bit Control (Preferred)
          2. 7.4.1.6.2 11-Bit Control
        7. 7.4.1.7  PWM Control
          1. 7.4.1.7.1 PWM Input Frequency Range
          2. 7.4.1.7.2 PWM Input Polarity
          3. 7.4.1.7.3 PWM Zero Detection
        8. 7.4.1.8  Start-up/Shutdown Ramp
        9. 7.4.1.9  Run-Time Ramp
        10. 7.4.1.10 High-Voltage Control A/B Ramp Select
        11. 7.4.1.11 LED Current Mapping Modes
        12. 7.4.1.12 Exponential Mapping
          1. 7.4.1.12.1 8-Bit Code Calculation
          2. 7.4.1.12.2 11-Bit Code Calculation
        13. 7.4.1.13 Linear Mapping
          1. 7.4.1.13.1 8-Bit Code Calculation
          2. 7.4.1.13.2 11-Bit Code Calculation
      2. 7.4.2 Low-Voltage LED Control
        1. 7.4.2.1  Integrated Charge Pump
        2. 7.4.2.2  Charge Pump Disabled
        3. 7.4.2.3  Automatic Gain
        4. 7.4.2.4  Automatic Gain (Flying Capacitor Detection)
        5. 7.4.2.5  1X Gain
        6. 7.4.2.6  2X Gain
        7. 7.4.2.7  Low-Voltage Current Sinks (LVLED1 to LVLED6)
        8. 7.4.2.8  Low-Voltage LED Biasing
        9. 7.4.2.9  Brightness Register Current Control
        10. 7.4.2.10 LED Current Mapping Modes
        11. 7.4.2.11 Exponential Mapping
        12. 7.4.2.12 Linear Mapping
        13. 7.4.2.13 Start-up/Shutdown Ramp
        14. 7.4.2.14 Run-Time Ramp
      3. 7.4.3 Low-Voltage LED Pattern Generator
        1. 7.4.3.1 Delay Time
        2. 7.4.3.2 Rise Time
        3. 7.4.3.3 Fall Time
        4. 7.4.3.4 High Period
        5. 7.4.3.5 Low Period
        6. 7.4.3.6 Low-Level Brightness
        7. 7.4.3.7 High-Level Brightness
      4. 7.4.4 Fault Flags/Protection Features
        1. 7.4.4.1 Open LED String (HVLED)
        2. 7.4.4.2 Shorted LED String (HVLED)
        3. 7.4.4.3 Open LED (LVLED)
        4. 7.4.4.4 Shorted LED (LVLED)
        5. 7.4.4.5 Overvoltage Protection (Inductive Boost)
        6. 7.4.4.6 Current Limit (Inductive Boost)
        7. 7.4.4.7 Current Limit (Charge Pump)
      5. 7.4.5 I2C-Compatible Interface
        1. 7.4.5.1 Start and Stop Conditions
        2. 7.4.5.2 I2C-Compatible Address
        3. 7.4.5.3 Transferring Data
    5. 7.5 Register Descriptions
      1. 7.5.1 Pattern Generator Registers
  8. 8 Applications and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Boost Converter Maximum Output Power (Boost)
          1. 8.2.2.1.1 Peak Current Limited
          2. 8.2.2.1.2 Output Voltage Limited
        2. 8.2.2.2 Boost Inductor Selection
        3. 8.2.2.3 Output Capacitor Selection
        4. 8.2.2.4 Schottky Diode Selection
        5. 8.2.2.5 Input Capacitor Selection
        6. 8.2.2.6 Maximum Output Power (Charge Pump)
        7. 8.2.2.7 Charge Pump Flying Capacitor Selection
        8. 8.2.2.8 Charge Pump Output Capacitor Selection
        9. 8.2.2.9 Charge Pump Input Capacitor Selection
      3. 8.2.3 Application Performance Plots
    3. 8.3 Initialization Set Up
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines (Boost)
      1. 10.1.1 Boost Output Capacitor Placement
      2. 10.1.2 Schottky Diode Placement
      3. 10.1.3 Inductor Placement
      4. 10.1.4 Boost Input Capacitor Placement
    2. 10.2 Layout Guidelines (Charge Pump)
      1. 10.2.1 Flying Capacitor (CP) Placement
      2. 10.2.2 Output Capacitor (CPOUT) Placement
      3. 10.2.3 Charge Pump Input Capacitor Placement
    3. 10.3 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

1 Features

  • Drives Three Parallel High-Voltage LED Strings for Display and Keypad Lighting
  • High-Voltage Strings Capable of up to 40-V Output Voltage and up to 90% Efficiency
  • Up to 30-mA per Current Sink (Both Backlight and Indicator)
  • 11-Bit High-Voltage LED Dimming
  • PWM Input for Content Adjustable Brightness Control (CABC)
  • Integrated 1-A/40-V MOSFET
  • Adaptive Boost Output to LED Voltages
  • Six Low-Voltage Current Sinks for Indicator LEDs
  • Integrated Charge Pump for Improved Efficiency and VIN Operating Range
  • Internal Pattern Generation Engine for Each Indicator LED
  • Fully Configurable LED Grouping and Control
  • Four Programmable Overvoltage Protection Thresholds (16 V, 24 V, 32 V, and 40 V)
  • Programmable 500-kHz and 1-MHz Switching Frequency
  • Overcurrent Protection
  • Thermal Shutdown Protection
  • 27 mm2 Total Solution Size

2 Applications

  • Power Source for Smart Phone Illumination
  • Display, Keypad and Indicator Illumination
  • RGB Indicator Driver

3 Description

The LM3633 11-bit LED driver provides high-performance backlight dimming for 1, 2, or 3 parallel high-voltage LED strings while delivering up to 90% efficiency. The boost converter with integrated 1-A, 40-V MOSFET automatically adjusts to LED forward voltage to minimize headroom voltage and effectively improve LED efficiency.

The LM3633 is a complete power source for backlight, keypad, and indicator LEDs in smartphone handsets. The high-voltage inductive boost converter provides the power for three parallel LED strings (HVLED1, HVLED2 and HVLED3). The integrated charge pump provides the bias for the six low-voltage indicator LEDs (LVLED1-LVLED6). All low-voltage current sinks can have a programmable pattern modulated onto their output current for a wide variety of blinking patterns.

An additional feature is a Pulse Width Modulation (PWM) control input for content adjustable backlight control, which can be used to control any high-voltage current sink.

The LM3633 is fully programmable via an I2C-compatible interface. The device operates over a 2.7-V to 5.5-V input voltage range and a −40°C to 85°C temperature range.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (MAX)
LM3633 DSBGA (20) 2.04 mm x 1.78 mm
  1. For all available packages, see the orderable addendum at the end of the datasheet.

Simplified Schematic

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Dual String Efficiency vs VIN

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