SLVSF14B September   2019  – August 2020 TPS61023

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  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 Undervoltage Lockout
      2. 7.3.2 Enable and Soft Start
      3. 7.3.3 Switching Frequency
      4. 7.3.4 Current Limit Operation
      5. 7.3.5 Pass-Through Operation
      6. 7.3.6 Overvoltage Protection
      7. 7.3.7 Output Short-to-Ground Protection
      8. 7.3.8 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
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Setting the Output Voltage
        2. 8.2.2.2 Inductor Selection
        3. 8.2.2.3 Output Capacitor Selection
        4. 8.2.2.4 Loop Stability, Feedforward Capacitor Selection
        5. 8.2.2.5 Input Capacitor Selection
      3. 8.2.3 Application Curves
  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 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    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
    1. 12.1 Package Option Addendum
    2. 12.2 Tape and Reel Information

Package Options

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

8.2.2.2 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 TPS61023 is designed to work with inductor values between 0.37 µH and 2.9 µH. Follow Equation 5 to Equation 7 to calculate the inductor peak current for the application. To calculate the current in the worst case, use the minimum input voltage, maximum output voltage, and maximum load current of the application. To have enough design margins, choose the inductor value with –30% tolerances, and low power-conversion efficiency for the calculation.

In a boost regulator, the inductor dc current can be calculated by Equation 5.

Equation 5. GUID-770BA782-A9DE-43D2-AF25-4A6238369EB5-low.gif

where

  • VOUT is the output voltage of the boost converter
  • IOUT is the output current of the boost converter
  • VIN is the input voltage of the boost converter
  • η is the power conversion efficiency, use 90% for most applications

The inductor ripple current is calculated by Equation 6.

Equation 6. GUID-E3826EFC-FAF1-4380-ABC8-B778363D06BB-low.gif

where

  • D is the duty cycle, which can be calculated by Equation 2
  • L is the inductance value of the inductor
  • fSW is the switching frequency
  • VIN is the input voltage of the boost converter

Therefore, the inductor peak current is calculated by Equation 7.

Equation 7. GUID-01116BBF-3171-4138-9A31-7EAF5CE7389E-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. The saturation current of the inductor must be higher than the calculated peak inductor current. Table 8-2 lists the recommended inductors for the TPS61023.

Table 8-2 Recommended Inductors for the TPS61023
PART NUMBER(1)L (µH)DCR MAX (mΩ)SATURATION CURRENT (A)SIZE (LxWxH)VENDOR
XEL4030-102ME19.789.04.0 × 4.0 × 3.1Coilcraft
74438357010113.59.64.1 x 4.1 x 3.1Wurth Elecktronik
HBME042A-1R0MS-99111.57.04.1 x 4.1 x 2.1Cyntec
(1) See Third-party Products disclaimer