ZHCSB15B May   2013  – October 2023 TPS54531

PRODUCTION DATA  

  1.   1
  2. 特性
  3. 应用
  4. 说明
  5. Revision History
  6. Pin Configuration and Functions
  7. 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
  8. 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  Voltage Reference (Vref)
      3. 7.3.3  Bootstrap Voltage (BOOT)
      4. 7.3.4  Enable and Adjustable Input Undervoltage Lockout (VIN UVLO)
      5. 7.3.5  Programmable Slow Start Using SS Pin
      6. 7.3.6  Error Amplifier
      7. 7.3.7  Slope Compensation
      8. 7.3.8  Current-Mode Compensation Design
      9. 7.3.9  Overcurrent Protection and Frequency Shift
      10. 7.3.10 Overvoltage Transient Protection
      11. 7.3.11 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Eco-mode
      2. 7.4.2 Operation With VIN < 3.5 V
      3. 7.4.3 Operation With EN Control
  9. 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  Custom Design With WEBENCH® Tools
        2. 8.2.2.2  Switching Frequency
        3. 8.2.2.3  Output Voltage Set Point
        4. 8.2.2.4  Undervoltage Lockout Set Point
        5. 8.2.2.5  Input Capacitors
        6. 8.2.2.6  Output Filter Components
          1. 8.2.2.6.1 Inductor Selection
          2. 8.2.2.6.2 Capacitor Selection
        7. 8.2.2.7  Compensation Components
        8. 8.2.2.8  Bootstrap Capacitor
        9. 8.2.2.9  Catch Diode
        10. 8.2.2.10 Slow-Start Capacitor
        11. 8.2.2.11 Output Voltage Limitations
        12. 8.2.2.12 Power Dissipation Estimate
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
      3. 8.4.3 Electromagnetic Interference (EMI) Considerations
  10. Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
        1. 9.1.1.1 Custom Design With WEBENCH® Tools
    2. 9.2 接收文档更新通知
    3. 9.3 支持资源
    4. 9.4 Trademarks
    5. 9.5 静电放电警告
    6. 9.6 术语表
  11. 10Mechanical, Packaging, and Orderable Information

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订购信息

Overview

The TPS54531 device is a 28-V, 5-A, step-down (buck) converter with an integrated high-side n-channel MOSFET. To improve performance during line and load transients, the device implements a constant-frequency, current mode control which reduces output capacitance and simplifies external frequency compensation design. The TPS54531 device has a preset switching frequency of 570 kHz.

The TPS54531 device requires a minimum input voltage of 3.5 V for normal operation. The EN pin has an internal pullup current source that can be used to adjust the input-voltage undervoltage lockout (UVLO) with two external resistors. In addition, the pullup current provides a default condition when the EN pin is floating for the device to operate. The operating current is 110 μA (typical) when not switching and under no load. When the device is disabled, the supply current is 1 μA (typical).

The integrated 80-mΩ high-side MOSFET allows for high-efficiency power-supply designs with continuous output currents up to 5 A.

The TPS54531 device reduces the external component count by integrating the boot recharge diode. The bias voltage for the integrated high-side MOSFET is supplied by an external capacitor on the BOOT to PH pin. The boot capacitor voltage is monitored by an UVLO circuit and turns the high-side MOSFET off when the voltage falls below a preset threshold of 2.1 V (typical). The output voltage can be stepped down to as low as the reference voltage.

By adding an external capacitor, the slow-start time of the TPS54531 device can be adjustable which enables flexible output filter selection.

To improve the efficiency at light load conditions, the TPS54531 device enters a special pulse skipping Eco-mode when the peak inductor current drops below 160 mA (typical).

The frequency foldback reduces the switching frequency during start-up and overcurrent conditions to help control the inductor current. The thermal shutdown provides the additional protection under fault conditions.