SLVSDP1F january   2017  – may 2023 TPS65235-1

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 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  Boost Converter
      2. 7.3.2  Linear Regulator and Current Limit
      3. 7.3.3  Boost Converter Current Limit
      4. 7.3.4  Charge Pump
      5. 7.3.5  Slew Rate Control
      6. 7.3.6  Short-Circuit Protection, Hiccup, and Overtemperature Protection
      7. 7.3.7  Tone Generation
      8. 7.3.8  Tone Detection
      9. 7.3.9  Audio Noise Rejection
      10. 7.3.10 Disable and Enable
      11. 7.3.11 Component Selection
        1. 7.3.11.1 Boost Inductor
        2. 7.3.11.2 Capacitor Selection
        3. 7.3.11.3 Surge Components
        4. 7.3.11.4 Consideration for Boost Filtering and LNB Noise
    4. 7.4 Device Functional Modes
    5. 7.5 Programming
      1. 7.5.1 Serial Interface Description
      2. 7.5.2 TPS65235-1 I2C Update Sequence
    6. 7.6 Register Maps
      1. 7.6.1 Control Register 1 (address = 0x00) [reset = 0x08]
      2. 7.6.2 Control Register 2 (address = 0x01) [reset = 0x09]
      3. 7.6.3 Status Register (address = 0x02) [reset = 0x29]
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 DiSEqc1.x Support
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 DiSEqc2.x Support
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  9. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  10. 10Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.3 Boost Converter Current Limit

The boost converter has the cycle-by-cycle peak current limit on the internal Power MOSFET switch to serve as the secondary protection when LNB output is hard short. With ISW bit default setting 0b on I2C control register 0x01, the switch current limit ISW is proportional as LDO current limit I(OCP) set by ISET pin resistor, and the relationship can be expressed as:

Equation 2. I S W   =   3   ×   I O C P   +   0.8   A

For the 5 V VIN, if LNB current load is up to 1 A, the ISW bit must be written as 1b, the switch current limit ISW for the internal Power MOSFET is:

Equation 3. I S W   =   5   ×   I O C P   +   0.8   A

While due to the high power loss at 5 V, VIN, it has a chance to trigger the thermal shutdown before the loading is up to 1 A, especially the VLNB output is high.