ZHCSFI8C June   2016  – June 2021 TPS62135

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  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 第三方产品免责声明
    2. 13.2 接收文档更新通知
    3. 13.3 支持资源
    4. 13.4 Trademarks
    5. 13.5 静电放电警告
    6. 13.6 术语表
  14. 14Mechanical, Packaging, and Orderable Information

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

10.3.1 LED Power Supply

The TPS62135x can be used as a power supply for power LEDs. The FB pin can be easily set down to lower values than nominal by using the SS/TR pin. With that, the voltage drop on the sense resistor is low to avoid excessive power loss. Since this pin provides 2.5 µA, the feedback pin voltage can be adjusted by an external resistor per Equation 18. This drop, proportional to the LED current, is used to regulate the output voltage (anode voltage) to a proper level to drive the LED. Both analog and PWM dimming are supported with the TPS62135x. Figure 10-83 shows an application circuit, tested with analog dimming:

GUID-BCBA6F67-2B2B-4BAA-B71B-688C76493E6F-low.gifFigure 10-83 Single Power LED Supply

The resistor at SS/TR defines the FB voltage. It is set to 350 mV by R5 = 140 kΩ using Equation 18. This cuts the losses on R4 to half from the nominal 0.7 V of feedback voltage while it still provides good accuracy.

Equation 18. GUID-F51E2E9B-F0ED-4590-9F56-D24BB20F3DCA-low.gif

The device now supplies a constant current set by resistor R4 from FB to GND. The minimum input voltage has to be rated according the forward voltage needed by the LED used. More information is available in the Application Note SLVA451.