JAJSCH6C June   2016  – June 2021 TPS62135

PRODUCTION DATA  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and 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 Parameter Measurement Information
    1. 8.1 Schematic
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Precise Enable
      2. 9.3.2 Power Good (PG)
      3. 9.3.3 Pin-Selectable Output Voltage (VSEL and FB2)
      4. 9.3.4 MODE
      5. 9.3.5 Undervoltage Lockout (UVLO)
      6. 9.3.6 Thermal Shutdown
    4. 9.4 Device Functional Modes
      1. 9.4.1 Pulse Width Modulation (PWM) Operation
      2. 9.4.2 Power Save Mode Operation (PWM/PFM)
      3. 9.4.3 100% Duty-Cycle Operation
      4. 9.4.4 HICCUP Current Limit And Short Circuit Protection (TPS62135 only)
      5. 9.4.5 Current Limit And Short Circuit Protection (TPS621351 only)
      6. 9.4.6 Soft-Start / Tracking (SS/TR)
      7. 9.4.7 Output Discharge Function (TPS62135 only)
      8. 9.4.8 Starting into a Pre-Biased Load (TPS621351 only)
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Programming the Output Voltage
      2. 10.1.2 External Component Selection
      3. 10.1.3 Inductor Selection
      4. 10.1.4 Capacitor Selection
        1. 10.1.4.1 Output Capacitor
        2. 10.1.4.2 Input Capacitor
        3. 10.1.4.3 Soft-Start Capacitor
      5. 10.1.5 Tracking Function
      6. 10.1.6 Output Filter and Loop Stability
    2. 10.2 Typical Applications
      1. 10.2.1 Typical Application with Adjustable Output Voltage
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
        3. 10.2.1.3 Application Curves
      2. 10.2.2 Typical Application using VSEL and FB2
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedure
        3. 10.2.2.3 Application Curves
    3. 10.3 System Examples
      1. 10.3.1 LED Power Supply
      2. 10.3.2 Powering Multiple Loads
      3. 10.3.3 Voltage Tracking
      4. 10.3.4 Precise Soft-Start Timing
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Thermal Considerations
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 Receiving Notification of Documentation Updates
    3. 13.3 サポート・リソース
    4. 13.4 Trademarks
    5. 13.5 静電気放電に関する注意事項
    6. 13.6 用語集
  14. 14Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

10.1.3 Inductor Selection

The TPS62135x is designed for a nominal 1-µH inductor. Larger values can be used to achieve a lower inductor current ripple but they may have a negative impact on efficiency and transient response. Smaller values than 1µH will cause a larger inductor current ripple which causes larger negative inductor current in forced PWM mode at low or no output current. Therefore they are not recommended at large voltages across the inductor as it is the case for high input voltages and low output voltages. With low output current in forced PWM mode this causes a larger negative inductor current peak which may exceed the negative current limit. At low or no output current and small inductor values the output voltage can therefore not be regulated any more. More detailed information on further LC combinations can be found in SLVA463.

The inductor selection is affected by several effects like inductor ripple current, output ripple voltage, PWM-to-PFM transition point and efficiency. In addition, the inductor selected has to be rated for appropriate saturation current and DC resistance (DCR). Equation 9 calculates the maximum inductor current.

Equation 9. GUID-9A8BEC90-932E-4019-BD1C-E0101B7331AE-low.gif
Equation 10. GUID-0F1A9F85-90D0-4FCF-A6CB-1990B039E7C9-low.gif

where:

IL(max) is the maximum inductor current

ΔIL is the Peak to Peak Inductor Ripple Current

L(min) is the minimum effective inductor value.

Calculating the maximum inductor current using the actual operating conditions gives the minimum saturation current of the inductor needed. A margin of about 20% is recommended to add. A larger inductor value is also useful to get lower ripple current, but increases the transient response time and size as well. The following inductors have been used with the TPS62135x and are recommended for use:

Table 10-2 List of Inductors
TYPEINDUCTANCE [µH]CURRENT [A](1)DIMENSIONS [LxBxH] mmMANUFACTURER
XFL4020-102ME1.0 µH, ±20%5.44 x 4 x 2.1Coilcraft
XAL4020-102ME1.0 µH, ±20%8.74 x 4 x 2.1Coilcraft
XAL4020-152ME1.5 µH, ±20%7.14 x 4 x 2.1Coilcraft
XFL4030-102ME1.0 µH, ±20%4.14 x 4 x 3.1Coilcraft
1277AS-H-1R0M (DFE322512C)1.0 µH, ±20%3.1(2)3.2 x 2.5 x 1.2Murata
(1) Lower of IRMS at 40°C rise or ISAT at 30% drop.
(2) For smallest size solutions that in average do not require the full output current TPS62135x can provide.

The inductor value also determines the load current at which Power Save Mode is entered:

Equation 11. GUID-4A535C30-3C3C-471A-9805-3E1766955FA3-low.gif