SLVSA92C November   2011  – September 2020 TPS63060 , TPS63061

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison
  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 Power Good
      2. 8.3.2 Soft-Start Function
      3. 8.3.3 Short-Circuit Protection
      4. 8.3.4 Overvoltage Protection
      5. 8.3.5 Undervoltage Lockout
      6. 8.3.6 Overtemperature Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Buck-Boost Operation
      2. 8.4.2 Control Loop
      3. 8.4.3 Power-Save Mode
      4. 8.4.4 Synchronization
      5. 8.4.5 Dynamic Voltage Positioning
      6. 8.4.6 Dynamic Current Limit
      7. 8.4.7 Device Enable
  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 Step One: Output Filter Design
        2. 9.2.2.2 Step Two: Inductor Selection
        3. 9.2.2.3 Step Three: Capacitor Selection
          1. 9.2.2.3.1 Input Capacitors
          2. 9.2.2.3.2 Output Capacitor
          3. 9.2.2.3.3 Bypass Capacitor
        4. 9.2.2.4 Step Four: Setting the Output Voltage
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9.2.2.2 Step Two: Inductor Selection

The inductor selection is affected by several parameters including inductor ripple current, output voltage ripple, transition point into power-save mode, and efficiency. See Table 9-3 for typical inductors.

Table 9-3 List of Recommended Inductors
Inductor Value (µH)Component Suplier(1)Size (L×W×H) (mm)Current Saturation (ISAT) (A)DCR (mΩ)
1Coilcraft XFL4020-1024 × 4 × 2.15.110.8
1TOKO DEM2815 1226AS-H-1R0N3 × 3.2 × 1.52.727
1.5Coilcraft XFL4020-1524 × 4 × 2.14.414.4
(1) See Section 12.1

For high efficiencies, the inductor should have a low dc resistance to minimize conduction losses. Especially at high-switching frequencies the core material has a higher 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, with the chosen inductance value, the peak current for the inductor in steady state operation can be calculated. Equation 1 and Equation 5 show how to calculate the peak current IPEAK. Only the equation which defines the switch current in boost mode is reported because this is providing the highest value of current and represents the critical current value for selecting the right inductor.

Equation 5. GUID-0F0BB700-6539-48B7-AD25-155ECD0BCD05-low.gif

where

  • D is the duty cycle during boost mode operation
  • fSW is the converter switching frequency (typical 2.4 MHz)
  • L is the selected inductor value
  • η is the estimated converter efficiency (use the number from the efficiency curves or 0.80 as an assumption)
  • 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. It's recommended to choose an inductor with a saturation current 20% higher than the value calculated using Equation 5. Possible inductors are listed in Table 9-3.