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

7.3.11.1 Boost Inductor

TI recommends the TPS65235-1 device to operate with a boost inductor value of 4.7 µH or 10 µH. The boost inductor must be able to support the peak current requirement to maintain the maximum LNB output current without saturation. Use Equation 5 to estimate the peak current of the boost inductor (Ipeak).

Equation 5. I p e a k   =   I O U T 1   -   D   +   1 2   ×   V I N   ×   D L   ×   f S

where

GUID-2D003725-04AE-4EED-9CCE-1BA2602BA948-low.gif

With a different inductance, the system has different gain and phase margins. Figure 7-5 shows a Bode plot of boost loop with 2 × 10 µF / 35 V of boost capacitor and 4.7 µH, 5.6 µH, 6.8 µH, 8.2 µH, and 10 µH of boost inductance. As the boost inductance increases, the 0-dB crossover frequency keeps relatively constant while reducing the phase and gain margins. With a 4.7-µH boost inductance, the phase margin is 66.96° and with a 10-µH inductance, the phase margin is 39.63°.

GUID-2C405577-AFAB-4F52-8E09-BBD79B454859-low.gif Figure 7-5 Gain and Phase Margin of the Boost Loop with Different Inductance (VIN = 12 V, VOUT = 18.2 V, ILOAD = 1 A, fSW = 1 MHz, 5 µF, Typical Bode Plot)