SLVSDQ6A July   2018  – November 2018 TL431LI , TL432LI

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Device Comparison Table
  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 Thermal Information
    4. 7.4 Recommended Operating Conditions
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Temperature Coefficient
    2. 8.2 Dynamic Impedance
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
    4. 9.4 Device Functional Modes
      1. 9.4.1 Open Loop (Comparator)
      2. 9.4.2 Closed Loop
  10. 10Applications and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 Comparator With Integrated Reference
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
          1. 10.2.1.2.1 Basic Operation
            1. 10.2.1.2.1.1 Overdrive
          2. 10.2.1.2.2 Output Voltage and Logic Input Level
            1. 10.2.1.2.2.1 Input Resistance
        3. 10.2.1.3 Application Curve
      2. 10.2.2 Precision Constant Current Sink
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedure
          1. 10.2.2.2.1 Basic Operation
            1. 10.2.2.2.1.1 Output Current Range and Accuracy
          2. 10.2.2.2.2 Power Consumption
      3. 10.2.3 Shunt Regulator/Reference
        1. 10.2.3.1 Design Requirements
        2. 10.2.3.2 Detailed Design Procedure
          1. 10.2.3.2.1 Programming Output/Cathode Voltage
          2. 10.2.3.2.2 Total Accuracy
          3. 10.2.3.2.3 Stability
          4. 10.2.3.2.4 Start-up Time
        3. 10.2.3.3 Application Curve
      4. 10.2.4 Isolated Flyback with Optocoupler
        1. 10.2.4.1 Design Requirements
          1. 10.2.4.1.1 Detailed Design Procedure
            1. 10.2.4.1.1.1 TL431 Feedback Loop Error Calculation
    3. 10.3 System Examples
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Related Links
    2. 13.2 Documentation Support
      1. 13.2.1 Device Nomenclature
      2. 13.2.2 Related Documentation
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Community Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

10.2.4.1 Design Requirements

The TL431LI is used in the feedback network on the secondary side in an isolated flyback with optocoupler design. Figure 25 shows the simplified flyback converter with the TL431LI. For this design example, use the parameters in Table 4 as the input parameters. In this example, a simplified design procedure will be discussed. The compensation network for the feedback network is beyond the scope of this section. Details on compensation network can be found on SLUA671.

Table 4. Design Parameters

DESIGN PARAMETER EXAMPLE VALUE
Voltage Output 15 V
Secondary Side Feedback Loop Accuracy < 3%