ZHCS026C December   2010  – February 2016 TPS57060-Q1

PRODUCTION DATA.  

  1. 1 特征
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      简化电路原理图
      2.      效率与负载电流间的关系
  4. 4 修订历史记录
  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  Fixed Frequency PWM Control
      2. 7.3.2  Slope Compensation Output Current
      3. 7.3.3  Low Dropout Operation and Bootstrap Voltage (BOOT)
      4. 7.3.4  Error Amplifier
      5. 7.3.5  Voltage Reference
      6. 7.3.6  Adjusting the Output Voltage
      7. 7.3.7  Enable and Adjusting Undervoltage Lockout (UVLO)
      8. 7.3.8  Slow Start and Tracking Pin (SS/TR)
      9. 7.3.9  Overload Recovery Circuit
      10. 7.3.10 Constant Switching Frequency and Timing Resistor (RT/CLK Pin)
      11. 7.3.11 Overcurrent Protection and Frequency Shift
      12. 7.3.12 Selecting the Switching Frequency
      13. 7.3.13 How to Interface to RT/CLK Pin
      14. 7.3.14 Power Good (PWRGD Pin)
      15. 7.3.15 Overvoltage Transient Protection
      16. 7.3.16 Thermal Shutdown
      17. 7.3.17 Small Signal Model for Loop Response
      18. 7.3.18 Simple Small-Signal Model for Peak Current-Mode Control
      19. 7.3.19 Small Signal Model for Frequency Compensation
    4. 7.4 Device Functional Modes
      1. 7.4.1 Sequencing
      2. 7.4.2 Pulse Skip Eco-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  Selecting the Switching Frequency
        2. 8.2.2.2  Output Inductor Selection (LO)
        3. 8.2.2.3  Output Capacitor
        4. 8.2.2.4  Catch Diode
        5. 8.2.2.5  Input Capacitor
        6. 8.2.2.6  Slow Start Capacitor
        7. 8.2.2.7  Bootstrap Capacitor Selection
        8. 8.2.2.8  Undervoltage Lockout Set Point
        9. 8.2.2.9  Output Voltage and Feedback Resistors Selection
        10. 8.2.2.10 Compensation
        11. 8.2.2.11 Discontinuous Mode and Eco Mode Boundary
      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 Power Dissipation Estimate
  11. 11器件和文档支持
    1. 11.1 器件支持
      1. 11.1.1 Third-Party Products Disclaimer
      2. 11.1.2 开发支持
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 社区资源
    4. 11.4 商标
    5. 11.5 静电放电警告
    6. 11.6 Glossary
  12. 12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

8.2.2.4 Catch Diode

The TPS57060-Q1 requires an external catch diode between the PH pin and GND. The selected diode must have a reverse voltage rating equal to or greater than Vinmax. The peak current rating of the diode must be greater than the maximum inductor current. The diode should also have a low forward voltage. Schottky diodes are typically a good choice for the catch diode due to their low forward voltage. The lower the forward voltage of the diode, the higher the efficiency of the regulator.

Typically, the higher the voltage and current ratings the diode has, the higher the forward voltage will be. Because the design example has an input voltage up to 48 V, a diode with a minimum of 60-V reverse voltage will be selected.

For the example design, the B160A Schottky diode is selected for its lower forward voltage and it comes in a larger package size which has good thermal characteristics over small devices. The typical forward voltage of the B160A is 0.50 V.

The diode must also be selected with an appropriate power rating. The diode conducts the output current during the off-time of the internal power switch. The off-time of the internal switch is a function of the maximum input voltage, the output voltage, and the switching frequency. The output current during the off-time is multiplied by the forward voltage of the diode which equals the conduction losses of the diode. At higher switch frequencies, the ac losses of the diode need to be taken into account. The ac losses of the diode are due to the charging and discharging of the junction capacitance and reverse recovery. Equation 37 is used to calculate the total power dissipation, conduction losses plus ac losses, of the diode.

The B160A has a junction capacitance of 110 pF. Using Equation 37, the selected diode will dissipate 0.297 W. This power dissipation, depending on mounting techniques, should produce a 5.9°C temperature rise in the diode when the input voltage is 48V and the load current is 0.5 A.

If the power supply spends a significant amount of time at light load currents or in sleep mode consider using a diode which has a low leakage current and slightly higher forward voltage drop.

Equation 37. TPS57060-Q1 eq39_lvsa25.gif