SLUS772G MARCH   2008  – June 2020 TPS40210 , TPS40211

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      Simplified Schematic
  4. Revision History
  5. Pin Configuration and Functions
    1.     Pin Functions
  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. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Soft Start
      2. 7.3.2  BP Regulator
      3. 7.3.3  Shutdown (DIS/EN Pin)
      4. 7.3.4  Minimum On-Time and Off-Time Considerations
      5. 7.3.5  Setting the Oscillator Frequency
      6. 7.3.6  Synchronizing the Oscillator
      7. 7.3.7  Current Sense and Overcurrent
      8. 7.3.8  Current Sense and Subharmonic Instability
      9. 7.3.9  Current Sense Filtering
      10. 7.3.10 Control Loop Considerations
      11. 7.3.11 Gate Drive Circuit
      12. 7.3.12 TPS40211
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation Near Minimum Input Voltage
      2. 7.4.2 Operation With DIS/EN Pin
  8. Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 12-V to 24-V Nonsynchronous Boost Regulator
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1  Custom Design with WEBENCH Tools
          2. 8.2.1.2.2  Duty Cycle Estimation
          3. 8.2.1.2.3  Inductor Selection
          4. 8.2.1.2.4  Rectifier Diode Selection
          5. 8.2.1.2.5  Output Capacitor Selection
          6. 8.2.1.2.6  Input Capacitor Selection
          7. 8.2.1.2.7  Current Sense and Current Limit
          8. 8.2.1.2.8  Current Sense Filter
          9. 8.2.1.2.9  Switching MOSFET Selection
          10. 8.2.1.2.10 Feedback Divider Resistors
          11. 8.2.1.2.11 Error Amplifier Compensation
          12. 8.2.1.2.12 RC Oscillator
          13. 8.2.1.2.13 Soft-Start Capacitor
          14. 8.2.1.2.14 Regulator Bypass
          15. 8.2.1.2.15 Bill of Materials
        3. 8.2.1.3 Application Curves
      2. 8.2.2 12-V Input, 700-mA LED Driver, Up to 35-V LED String
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
      2. 11.1.2 Related Devices
      3. 11.1.3 Development Support
        1. 11.1.3.1 Custom Design with WEBENCH Tools
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Related Links
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

Current Sense and Current Limit

The maximum allowable current sense resistor value is limited by both the current limit and sub-harmonic stability. These two limitations are given by Equation 49 and Equation 50.

Equation 49. TPS40210 TPS40211 q_risns1_lus772.gif
Equation 50. TPS40210 TPS40211 q_risns2_lus772.gif

With 10% margin on the current limit trip point (the 1.1 factor) and assuming a maximum gate drive current of 500 mA, the current limit requires a resistor less than 15.4 mΩ and stability requires a sense resistor less than 134 mΩ. A 10-mΩ resistor is selected. Approximately 2 mΩ of routing resistance is added in compensation calculations.

The power dissipation in RISNS is calculated by Equation 51.

Equation 51. TPS40210 TPS40211 q_pdiss_v2_lus772.gif

At maximum duty cycle, this is 0.253 W.