SLVSD82B April   2017  – February 2021 TLV61046A

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Undervoltage Lockout
      2. 7.3.2 Enable and Disable
      3. 7.3.3 Soft Start
      4. 7.3.4 Overvoltage Protection
      5. 7.3.5 Output Short Circuit Protection
      6. 7.3.6 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 PWM Mode
      2. 7.4.2 Power Save Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application - 12-V Output Boost Converter
      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 Programming the Output Voltage
        3. 8.2.2.3 Inductor Selection
        4. 8.2.2.4 Input and Output Capacitor Selection
      3. 8.2.3 Application Performance Curves
    3. 8.3 System Examples
      1. 8.3.1 Fixed 12-V Output Voltage with Three External Components
  9. 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 Development Support
        1. 11.1.2.1 Custom Design With WEBENCH® Tools
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.2.3 Inductor Selection

Because the selection of the inductor affects steady state operation, transient behavior, and loop stability, the inductor is the most important component in power regulator design. There are three important inductor specifications, inductor value, saturation current, and dc resistance (DCR).

The TLV61046A is designed to work with inductor values between 2.2 µH and 22 µH. Follow Equation 2 to Equation 4 to calculate the peak current of the inductor for the application. To calculate the peak current in the worst case, use the minimum input voltage, maximum output voltage, and maximum load current of the application. To have enough design margin, choose the inductor value with -30% tolerance, and a low power-conversion efficiency for the calculation.

In a boost regulator, the inductor dc current can be calculated with Equation 2.

Equation 2. GUID-4637E5D6-1F4C-4819-8DDF-4B0DEA18C7DA-low.gif

where

  • VOUT is output voltage
  • IOUT is output current
  • VIN is input voltage
  • η is power conversion efficiency, use 80% for most applications

The inductor ripple current is calculated with Equation 3 for an asynchronous boost converter in continuous conduction mode (CCM).

Equation 3. GUID-82810853-439D-4527-8F9C-FDEE879BBE9E-low.gif

where

  • ΔIL(P-P) is inductor ripple current
  • L is inductor value
  • fSW is switching frequency
  • VOUT is output voltage
  • VIN is input voltage

Therefore, the inductor peak current is calculated with Equation 4.

Equation 4. GUID-DBBD2342-8D88-4E24-BE2C-447DEEAF025D-low.gif

Normally, it is advisable to work with an inductor peak-to-peak current of less than 40% of the average inductor current for maximum output current. A smaller ripple from a larger valued inductor reduces the magnetic hysteresis losses in the inductor and EMI. But in the same way, load transient response time is increased. Because the TLV61046A is for relatively small output current application, the inductor peak-to-peak current can be as high as 200% of the average current with a small inductor value, which means the TLV61046A always works in DCM mode. Table 8-2 lists the recommended inductors for the TLV61046A.

Table 8-2 Recommended Inductors for the TLV61046A
PART NUMBERL(µH)DCR MAX (mΩ)SATURATION CURRENT (A)SIZE (LxWxH)VENDOR(1)
FDSD0420-H-100M102002.54.2x4.2x2.0Toko
CDRH3D23/HP101981.024.0x4.0x2.5Sumida
74438336100103222.353.2x3.2x2.0Wurth
VLS4012-4R7M4.71321.14.0x4.0x1.2TDK