SLVS790E November   2007  – April 2019 TPS61165

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application
  4. 4 Revision History
  5. 5 Device Options
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Recommended Operating Conditions
    3. 7.3 Thermal Information
    4. 7.4 Electrical Characteristics
    5. 7.5 Timing Requirements
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Soft Start-Up
      2. 8.3.2 Open LED Protection
      3. 8.3.3 Undervoltage Lockout
      4. 8.3.4 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Maximum Output Current
      2. 9.1.2 Inductor Selection
      3. 9.1.3 Schottky Diode Selection
      4. 9.1.4 Compensation Capacitor Selection
      5. 9.1.5 Input and Output Capacitor Selection
    2. 9.2 Typical Applications
      1. 9.2.1 TPS61165 Typical Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 LED Brightness Dimming Mode Selection
          2. 9.2.1.2.2 PWM Brightness Dimming
          3. 9.2.1.2.3 Digital One-Wire Brightness Dimming
          4. 9.2.1.2.4 EasyScale: One-Wire Digital Dimming
          5. 9.2.1.2.5 Current Program
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Additional Application Circuits
    3. 9.3 Do's and Don'ts
  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 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9.1.1 Maximum Output Current

The overcurrent limit in a boost converter limits the maximum input current and thus maximum input power for a given input voltage. Maximum output power is less than maximum input power due to power conversion losses. Therefore, the current limit setting, input voltage, output voltage and efficiency can all change maximum current output. The current limit clamps the peak inductor current; therefore, the ripple has to be subtracted to derive maximum dc current. The ripple current is a function of switching frequency, inductor value and duty cycle. The following equations take into account of all the above factors for maximum output current calculation.

Equation 1. TPS61165 q3r_lvs790.gif

where

  • Ip = inductor peak to peak ripple
  • L = inductor value
  • Vf = Schottky diode forward voltage
  • Fs = switching frequency
  • Vout = output voltage of the boost converter. It is equal to the sum of VFB and the voltage drop across LEDs.
Equation 2. TPS61165 q4_ioutmax_lvs790.gif

where

  • Iout_max = Maximum output current of the boost converter
  • Ilim = overcurrent limit
  • η = efficiency

For instance, when VIN is 3 V, 8 LEDs output equivalent to VOUT of 26 V, the inductor is 22 μH, the Schottky forward voltage is 0.2 V, the maximum output current is then 110 mA in typical condition. When VIN is 5 V, 10 LEDs output equivalent to VOUT of 32 V, the inductor is 22 μH, the Schottky forward voltage is 0.2 V, the maximum output current is 150 mA in typical condition.