SLUSD66D September   2019  – February 2021 TPS92520-Q1

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 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 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  Buck Converter Switching Operation
      2. 7.3.2  Switching Frequency and Adaptive On-Time Control
      3. 7.3.3  Minimum On-Time, Off-Time, and Inductor Ripple
      4. 7.3.4  LED Current Regulation and Error Amplifier
      5. 7.3.5  Start-up Sequence
      6. 7.3.6  Analog Dimming and Forced Continuous Conduction Mode
      7. 7.3.7  External PWM Dimming and Input Undervoltage Lockout (UVLO)
      8. 7.3.8  Internal PWM Dimming
      9. 7.3.9  Shunt FET Dimming or Matrix Beam Application
      10. 7.3.10 Bias Supply
      11. 7.3.11 Bootstrap Supply
      12. 7.3.12 ADC
        1. 7.3.12.1 Input Voltage Measurement: VINx
        2. 7.3.12.2 LED Voltage Measurement: CSNx
        3. 7.3.12.3 Bias Supply Measurement: V5D
        4. 7.3.12.4 External Limp-Home Input Measurement: LHI
        5. 7.3.12.5 Junction Temperature Measurement: TEMP
      13. 7.3.13 Faults and Diagnostics
      14. 7.3.14 Output Short Circuit Fault
      15. 7.3.15 Output Open Circuit Fault
    4. 7.4 Device Functional Modes
      1. 7.4.1 Power On Reset (POR)
      2. 7.4.2 Detect SPI Communication
      3. 7.4.3 Standalone Mode
      4. 7.4.4 Load Mode
      5. 7.4.5 Run Mode
      6. 7.4.6 Sleep Mode
      7. 7.4.7 Limp-Home Mode
    5. 7.5 Programming
      1. 7.5.1 Serial Interface
      2. 7.5.2 Command Frame
      3. 7.5.3 Response Frame
        1. 7.5.3.1 Read Response Frame Format
        2. 7.5.3.2 Write Response Frame Format
        3. 7.5.3.3 Write Error/POR Frame Format
      4. 7.5.4 SPI Error
      5. 7.5.5 SPI for Multiple Slave Devices in Parallel Configuration
      6. 7.5.6 SPI for Multiple Slave Devices in Daisy Chain Configuration
    6. 7.6 Register Maps
      1. 7.6.1 Configuration Registers
        1. 7.6.1.1 SYSCFG1 Register (address = 0x00) [reset = 0x10]
        2. 7.6.1.2 SYSCFG2 Register (address = 0x01) [reset = 0x00]
        3. 7.6.1.3 CMWTAP Register (address = 0x02) [reset = 0x08]
      2. 7.6.2 STATUS Registers
        1. 7.6.2.1 STATUS1 Register (address = 0x03)
        2. 7.6.2.2 STATUS2 Register (address = 0x04)
        3. 7.6.2.3 STATUS3 Register (address = 0x05)
      3. 7.6.3 Device Control Registers
        1. 7.6.3.1  Thermal Warning Limit (address = 0x06) [reset = 0x8A]
        2. 7.6.3.2  SLEEP Command (address = 0x07) [reset = 0x00]
        3. 7.6.3.3  CH1IADJL Control Register (address = 0x08) [reset = 0x00]
        4. 7.6.3.4  CH1IADJH Control Register (address = 0x09) [reset = 0x00]
        5. 7.6.3.5  CH2IADJL Control Register (address = 0x0A) [reset = 0x00]
        6. 7.6.3.6  CH2IADJH Control Register (address = 0x0B) [reset = 0x00]
        7. 7.6.3.7  PWMDIV Register (address = 0x0C) [reset = 0x04]
        8. 7.6.3.8  CH1PWML Register (address = 0x0D) [reset = 0x00]
        9. 7.6.3.9  CH1PWMH Register (address = 0x0E) [reset = 0x00]
        10. 7.6.3.10 CH2PWML Register (address = 0x0F) [reset = 0x00]
        11. 7.6.3.11 CH2PWMH Register (address = 0x10) [reset = 0x00]
        12. 7.6.3.12 CH1TON Register (address = 0x11) [reset = 0x07]
        13. 7.6.3.13 CH2TON Register (address = 0x12) [reset = 0x07]
      4. 7.6.4 ADC Measurements
        1. 7.6.4.1  CH1VIN Measurement (address = 0x13)
        2. 7.6.4.2  CH1VLED Measurement (address = 0x14)
        3. 7.6.4.3  CH1VLEDON Measurement (address = 0x15)
        4. 7.6.4.4  CH1VLEDOFF Measurement (address = 0x16)
        5. 7.6.4.5  CH2VIN Measurement (address = 0x17)
        6. 7.6.4.6  CH2VLED Measurement (address = 0x18)
        7. 7.6.4.7  CH2VLEDON Measurement (address = 0x19)
        8. 7.6.4.8  CH2VLEDOFF Measurement (address = 0x1A)
        9. 7.6.4.9  TEMPL Measurement (address = 0x1B)
        10. 7.6.4.10 TEMPH Measurement (address = 0x1C)
        11. 7.6.4.11 V5D Measurement (address = 0x1D)
      5. 7.6.5 Limp-Home Configuration and Command Registers
        1. 7.6.5.1  LHCFG1 Register (address = 0x1E) [reset =0x00]
        2. 7.6.5.2  LHCFG2 Register (address = 0x1F) [reset =0x00h]
        3. 7.6.5.3  LHIL Measurement (address = 0x20)
        4. 7.6.5.4  LHIH Measurement (address = 0x21)
        5. 7.6.5.5  LHIFILTL Register (address = 0x22)
        6. 7.6.5.6  LHIFILTH Register (address = 0x23)
        7. 7.6.5.7  LH1IADJL Register (address = 0x24) [reset = 0x00]
        8. 7.6.5.8  LH1IADJH Register (address = 0x25) [reset = 0x00]
        9. 7.6.5.9  LH2IADJL Register (address = 0x26) [reset = 0x00]
        10. 7.6.5.10 LH2IADJH Register (address = 0x27) [reset = 0x00]
        11. 7.6.5.11 LH1PWML Register (address = 0x28) [reset = 0x00]
        12. 7.6.5.12 LH1PWMH Register (address = 0x29) [reset = 0x00]
        13. 7.6.5.13 LH2PWML Register (address = 0x2A) [reset = 0x00]
        14. 7.6.5.14 LH2PWMH Register (address = 0x2B) [reset = 0x00]
        15. 7.6.5.15 LH1TON Register (address = 0x2C) [reset = 0x07]
        16. 7.6.5.16 LH2TON Register (address = 0x2D) [reset = 0x07]
      6. 7.6.6 RESET Register (address = 0x2E) (Write-Only)
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1  Duty Cycle Consideration
      2. 8.1.2  Switching Frequency Selection
      3. 8.1.3  LED Current Set Point
      4. 8.1.4  Inductor Selection
      5. 8.1.5  Output Capacitor Selection
      6. 8.1.6  Input Capacitor Selection
      7. 8.1.7  Bootstrap Capacitor Selection
      8. 8.1.8  Compensation Capacitor Selection
      9. 8.1.9  Input Undervoltage Protection
      10. 8.1.10 CSN Protection Diode
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
        1. 8.2.1.1 Detailed Design Procedure
          1. 8.2.1.1.1 Calculating Duty Cycle
          2. 8.2.1.1.2 Calculating Minimum On-Time and Off-Time
          3. 8.2.1.1.3 Minimum Switching Frequency
          4. 8.2.1.1.4 LED Current Set Point
          5. 8.2.1.1.5 Inductor Selection
          6. 8.2.1.1.6 Output Capacitor Selection
          7. 8.2.1.1.7 Bootstrap Capacitor Selection
          8. 8.2.1.1.8 Compensation Capacitor Selection
          9. 8.2.1.1.9 External Channel Enable and PWM dimming
      2. 8.2.2 Application Curves
    3. 8.3 Initialization Setup
      1. 8.3.1 Initialize Device without Watchdog timer
      2. 8.3.2 Initialize Device with Watchdog Timer
      3. 8.3.3 Limp-Home Mode
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Compact Layout for EMI Reduction
        1. 10.1.1.1 Ground Plane
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

10.1.1 Compact Layout for EMI Reduction

Radiated EMI is generated by the high di/dt from pulsing currents in switching converters. The larger the area covered by the path of a pulsing current, the more electromagnetic emission is generated. The key to minimize radiated EMI is to identify the pulsing current path and minimize the area of the path. In buck converters, the pulsing current path is from the VIN side of the input capacitors through the HS switch, through the LS switch, and then returns to the ground of the input capacitor.

High-frequency ceramic bypass capacitors at the input side provide primary path for the high di/dt components of the pulsing current. Placing ceramic capacitors as close as possible to the VIN and PGND pins is the key to EMI reduction.

The PCB copper connection of the SW pin to the inductor must be as short as possible and just wide enough to carry the LED current without excessive heating. Short, thick traces or, copper pours (shapes), must be used for high current conduction path to minimize parasitic resistance. Place the output capacitor close to the CSN pin and grounded closely to the PGND pin.