SLVSCN0C june   2014  – may 2023 TPS65263

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Adjusting the Output Voltage
      2. 8.3.2  Enable and Adjusting UVLO
      3. 8.3.3  Soft-Start Time
      4. 8.3.4  Power-Up Sequencing
      5. 8.3.5  V7V Low Dropout Regulator and Bootstrap
      6. 8.3.6  Out-of-Phase Operation
      7. 8.3.7  Output Overvoltage Protection (OVP)
      8. 8.3.8  Pulse Skipping Mode (PSM)
      9. 8.3.9  Slope Compensation
      10. 8.3.10 Overcurrent Protection
        1. 8.3.10.1 High-Side MOSFET Overcurrent Protection
        2. 8.3.10.2 Low-Side MOSFET Overcurrent Protection
      11. 8.3.11 Power Good
      12. 8.3.12 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Serial Interface Description
      2. 8.4.2 I2C Update Sequence
    5. 8.5 Register Maps
      1. 8.5.1 Register Description
      2. 8.5.2 VOUT1_SEL: Vout1 Voltage Selection Register (offset = 0x00H)
      3. 8.5.3 VOUT2_SEL: Vout2 Voltage Selection Register (offset = 0x01H)
      4. 8.5.4 VOUT3_SEL: Vout3 Voltage Selection Register (offset = 0x02H)
      5. 8.5.5 VOUT1_COM: Buck1 Command Register (offset = 0x03H)
      6. 8.5.6 VOUT2_COM: Buck2 Command Register (offset = 0x04H)
      7. 8.5.7 VOUT3_COM: Buck3 Command Register (offset = 0x05H)
      8. 8.5.8 SYS_STATUS: System Status Register (offset = 0x06H)
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Output Inductor Selection
        2. 9.2.2.2 Output Capacitor Selection
        3. 9.2.2.3 Input Capacitor Selection
        4. 9.2.2.4 Loop Compensation
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  12. 11Mechanical, Packaging, and Orderable Information

9.2.2.1 Output Inductor Selection

To calculate the value of the output inductor, use Equation 7. LIR is a coefficient that represents the amount of inductor ripple current relative to the maximum output current. The inductor ripple current is filtered by the output capacitor. Therefore, choosing high inductor ripple currents impact the selection of the output capacitor because the output capacitor must have a ripple current rating equal to or greater than the inductor ripple current. In general, the inductor ripple value is at the discretion of the designer; however, LIR is normally from 0.1 to 0.3 for the majority of applications.

Equation 7. GUID-FD5A2084-8C48-41AF-AC38-8EF9C6CDBE71-low.gif

For the output filter inductor, it is important that the RMS current and saturation current ratings not be exceeded. The RMS and peak inductor current can be found from Equation 9 and Equation 10.

Equation 8. GUID-D4E80618-3A37-4D6C-92CB-17331BE96814-low.gif
Equation 9. GUID-92DDC173-00AF-49C6-9ED5-CA0E6583DC26-low.gif
Equation 10. GUID-2AD79D5D-CDE6-4179-A6D6-D0C4889EA040-low.gif

The current flowing through the inductor is the inductor ripple current plus the output current. During power up, faults or transient load conditions, the inductor current can increase above the calculated peak inductor current level calculated above. In transient conditions, the inductor current can increase up to the switch current limit of the device. For this reason, the most conservative approach is to specify an inductor with a saturation current rating equal to or greater than the switch current limit rather than the peak inductor current.