SLVS916I July   2010  – October 2019 TPS63020 , TPS63021

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Efficiency vs Output Current
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 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 Dynamic Voltage Positioning
      2. 7.3.2 Dynamic Current Limit
      3. 7.3.3 Device Enable
      4. 7.3.4 Power Good
      5. 7.3.5 Overvoltage Protection
      6. 7.3.6 Undervoltage Lockout
      7. 7.3.7 Overtemperature Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Soft-start and Short Circuit Protection
      2. 7.4.2 Buck-Boost Operation
      3. 7.4.3 Control Loop
      4. 7.4.4 Power Save Mode and Synchronization
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Custom Design with WEBENCH Tools
        2. 8.2.2.2 Inductor Selection
        3. 8.2.2.3 Output Capacitor Selection
        4. 8.2.2.4 Input Capacitor Selection
        5. 8.2.2.5 Bypass Capacitor
      3. 8.2.3 Setting The Output Voltage
      4. 8.2.4 Application Curves
    3. 8.3 System Examples
      1. 8.3.1 Improved Transient Response for 2 A Load Current
      2. 8.3.2 Supercapacitor Backup Power Supply With Active Cell Balancing
      3. 8.3.3 Low-Power TEC Driver
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Device Support
      1. 11.2.1 Custom Design with WEBENCH Tools
      2. 11.2.2 Third-Party Products Disclaimer
    3. 11.3 Documentation Support
      1. 11.3.1 Related Documentation
    4. 11.4 Related Links
    5. 11.5 Support Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.2.2 Inductor Selection

The inductor selection is affected by several parameters such as the following:

  • Inductor ripple current
  • Output voltage ripple
  • Transition point into Power Save Mode
  • Efficiency

See Table 2 for a list of typical inductors.

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. Use Equation 2 to avoid saturation of the inductor when calculating the peak current for the inductor in steady state operation. 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 1. TPS63020 TPS63021 q1_boost_lvsa92.gif
Equation 2. TPS63020 TPS63021 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 0.9 as an assumption)

NOTE

The calculation must be done for the minimum input voltage in boost mode.

Calculating the maximum inductor current using the actual operating conditions gives the minimum saturation current of the inductor needed. It is recommended to choose an inductor with a saturation current 20% higher than the value calculated using Equation 2. Table 2 lists the possible inductors.

Table 2. List of Recommended Inductors (1)

INDUCTOR VALUE [µH] SATURATION CURRENT [A] DCR [mΩ] PART NUMBER MANUFACTURER SIZE (LxWxH mm)
1.5 5.1 15 XFL4020-152ME Coilcraft 4 x 4 x 2.1
1.5 5.4 24 FDV0530S-H-1R5M muRata 5 x 5 x 3