ZHCSCO8E June   2014  – May 2019 TPS65283 , TPS65283-1

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 典型电路原理图
    1.     效率，Vin = 12V，PSM
  5. 5 修订历史记录
  6. 6 说明 （续）
  7. 7 Pin Configuration and Functions
    1.     Pin Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 Handling Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Typical Characteristics
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Power Switch Detailed Description
        1. 9.3.1.1 Overcurrent Condition
        2. 9.3.1.2 Reverse Current and Voltage Protection
        3. 9.3.1.3 nFAULT Response
        4. 9.3.1.4 UVLO
        5. 9.3.1.5 Enable and Output Discharge
        6. 9.3.1.6 Power Switch Input and Output Capacitance
        7. 9.3.1.7 Programming the Current-Limit Threshold
      2. 9.3.2 Buck DC-DC Converter Detailed Description
        1. 9.3.2.1  Output Voltage
        2. 9.3.2.2  Adjustable Switching Frequency
        3. 9.3.2.3  Synchronization
        4. 9.3.2.4  Error Amplifier
        5. 9.3.2.5  Slope Compensation
        6. 9.3.2.6  Enable and Adjusting UVLO
        7. 9.3.2.7  Internal V7V Regulator
        8. 9.3.2.8  Short Circuit Protection
          1. 9.3.2.8.1 High-Side MOSFET Overcurrent Protection
          2. 9.3.2.8.2 Low-Side MOSFET Overcurrent Protection
        9. 9.3.2.9  Bootstrap Voltage (BST) and Low Dropout Operation
        10. 9.3.2.10 Output Overvoltage Protection (OVP)
        11. 9.3.2.11 Power Good
        12. 9.3.2.12 Power-Up Sequencing
        13. 9.3.2.13 Thermal Performance
    4. 9.4 Device Functional Modes
      1. 9.4.1 Operation With VIN < 4.5 V (Minimum VIN)
      2. 9.4.2 Operation With EN Control
      3. 9.4.3 Operation at Light Loads
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Output Voltage Setting
        2. 10.2.2.2 Bootstrap Capacitor Selection
        3. 10.2.2.3 Inductor Selection
        4. 10.2.2.4 Output Capacitor Selection
        5. 10.2.2.5 Input Capacitor Selection
        6. 10.2.2.6 Minimum Output Voltage
        7. 10.2.2.7 Compensation Component Selection
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 PCB Layout Recommendation
      2. 12.1.2 Power Dissipation and Junction Temperature
    2. 12.2 Layout Example
  13. 13器件和文档支持
    1. 13.1 文档支持
      1. 13.1.1 相关链接
    2. 13.2 商标
    3. 13.3 静电放电警告
    4. 13.4 Glossary
  14. 14机械、封装和可订购信息

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

12.1.2 Power Dissipation and Junction Temperature

The total power dissipation inside TPS65283, TPS65283-1 should not to exceed the maximum allowable junction temperature of 125°C. The maximum allowable power dissipation is a function of the thermal resistance of the package (RθJA) and ambient temperature.

The following analysis gives an approximation in calculating junction temperature based on the power dissipation in the package. However, note that thermal analysis is strongly dependent on additional system-level factors. Such factors include air flow, board layout, copper thickness and surface area, and proximity to other devices dissipating power. Good thermal design practice must include all system-level factors in addition to individual component analysis.

To calculate the temperature inside the device under continuous load, use the following procedure.

  1. Define the total continuous current through buck converter (including the load current through power switches). Make sure the continuous current does not exceed maximum load current requirement.
  2. From the graphs in this section, determine the expected losses (y-axis) in watts for buck converter inside the device. The loss PD_BUCK depends on the input supply and the selected switching frequency.
  3. Determine the load current IOUT through the power switches. Read RDS(on) of power switch from the typical characteristics graph.
  4. Calculate the power loss through power switches with PD_PW = RDS(on) × IOUT.
  5. The Thermal Information table provides the thermal resistance RθJA for specific packages and board layouts.
  6. To calculate the maximum temperature inside the IC, use Equation 21.
    7. Equation 21. TJ = (PD_BUCK + PD_PW ) × RθJA + TA

    where

    • TA = Ambient temperature (°C)
    • RθJA = Thermal resistance (°C/W)
    • PD_BUCK = Total power dissipation in buck converter (W)
    • PD_PW = Total power dissipation in power switches (W)
TPS65283 TPS65283-1 C012_SLVSCL3.png
Figure 56. Power Dissipation of TPS65283
TPS65283 TPS65283-1 thermal_signature_TPS65283EVM_slvscl3.gif
A. VIN = 12 V, Vout1 = 1.2 V / 3 A, Vout2 = 5 V / 2 A, VSW_in = 5 V, ISW_OUT = 1.2 A
B. EVM board: 4-layer PCB, 1.6-mm thickness, 35-µm copper thickness, 68-mm × 68-mm size, 9 vias at thermal pad
Figure 57. Thermal Signature of TPS65283EVM