SLVS696D October   2008  – April 2020 TPS63030 , TPS63031

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Schematic
      2.      Efficiency versus Output Current
  4. 4 Revision History
  5. 5 Output Voltage Options
  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 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagrams
    3. 8.3 Feature Description
      1. 8.3.1 Device Enable
      2. 8.3.2 Undervoltage Lockout
      3. 8.3.3 Overtemperature Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Soft Start and Short Circuit Protection
      2. 8.4.2 Buck-Boost Operation
      3. 8.4.3 Power-Save Mode and Synchronization
  9. 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 Programming the Output Voltage
        2. 9.2.2.2 Inductor Selection
        3. 9.2.2.3 Capacitor Selection
          1. 9.2.2.3.1 Input Capacitor
          2. 9.2.2.3.2 Bypass Capacitor
          3. 9.2.2.3.3 Output Capacitor
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Related Links
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9.2.2.2 Inductor Selection

The inductor selection is affected by several parameter like inductor ripple current, output voltage ripple, transition point into power-save mode, and efficiency. See Table 3 for typical inductors.

Table 3. List of Recommended Inductors

VENDOR INDUCTOR SERIES
Coilcraft LPS3015
EPL3010
Murata LQH3NP
Tajo Yuden NR3015

For high efficiencies, the inductor must have a low DC resistance to minimize conduction losses. Especially at high-switching frequencies, the core material has a high impact on efficiency. When using small chip inductors, the efficiency is reduced mainly due to higher inductor core losses. This needs to be considered when selecting the appropriate inductor. The inductor value determines the inductor ripple current. The larger the inductor value, the smaller the inductor ripple current and the lower the conduction losses of the converter. Conversely, larger inductor values cause a slower load transient response. To avoid saturation of the inductor, the peak current for the inductor in steady state operation is calculated using Equation 3. Only the equation which defines the switch current in boost mode is shown, because this provides the highest value of current and represents the critical current value for selecting the right inductor.

Equation 2. TPS63030 TPS63031 q1_boost_lvsa92.gif
Equation 3. TPS63030 TPS63031 peak_current_boost_lvsa92.gif

where

  • D = duty cycle in boost mode
  • f = converter switching frequency (typical 2.5 MHz)
  • L = inductor value
  • η = estimated converter efficiency (use the number from the efficiency curves or 0.90 as an assumption)

NOTE

The calculation must be done for the minimum input voltage which is possible to have in boost mode.

Calculating the maximum inductor current using the actual operating conditions gives the minimum saturation current of the inductor needed. TI recommends to choose an inductor with a saturation current 20% higher than the value calculated using Equation 3. Possible inductors are listed in Table 3.