ZHCSPP3 July   2022 TPS563300

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Peak Current Mode
      2. 7.3.2  Pulse Frequency Modulation
      3. 7.3.3  Voltage Reference
      4. 7.3.4  Output Voltage Setting
      5. 7.3.5  Enable and Adjusting Undervoltage Lockout
      6. 7.3.6  Minimum On Time, Minimum Off Time, and Frequency Foldback
      7. 7.3.7  Frequency Spread Spectrum
      8. 7.3.8  Overvoltage Protection
      9. 7.3.9  Overcurrent and Undervoltage Protection
      10. 7.3.10 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Modes Overview
      2. 7.4.2 Heavy Load Operation
      3. 7.4.3 Light-Load Operation
      4. 7.4.4 Dropout Operation
      5. 7.4.5 Minimum On-Time Operation
      6. 7.4.6 Shutdown 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 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Output Voltage Resistors Selection
        3. 8.2.2.3 Bootstrap Capacitor Selection
        4. 8.2.2.4 Undervoltage Lockout Set Point
        5. 8.2.2.5 Output Inductor Selection
        6. 8.2.2.6 Output Capacitor Selection
        7. 8.2.2.7 Input Capacitor Selection
        8. 8.2.2.8 Feedforward Capacitor CFF Selection
        9. 8.2.2.9 Maximum Ambient Temperature
      3. 8.2.3 Application Curves
    3. 8.3 Best Design Practices
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  9. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 第三方产品免责声明
      2. 9.1.2 Development Support
        1. 9.1.2.1 Custom Design With WEBENCH® Tools
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 接收文档更新通知
    4. 9.4 支持资源
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 术语表
  10. 10Mechanical, Packaging, and Orderable Information

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7.1 Overview

The TPS563300 is a 28-V, 3-A, synchronous buck (step-down) converter with two integrated n-channel MOSFETs. The device employs fixed-frequency peak current control mode for fast transient response and good line and load regulation. With the optimized internal loop compensation, the device eliminates the external compensation components over a wide range of output voltage and switching frequency.

The integrated 76-mΩ and 32-mΩ MOSFETs allow for high-efficiency power supply designs with continuous output currents up to 3 A. The feedback reference voltage is designed at 0.8 V. The output voltage can be stepped down from 0.8 V to 22 V. The device is ideally suited for systems powered from the following power-bus rails:

  • 5-V
  • 12-V
  • 19-V
  • 24-V

The TPS563300 has been designed for safe monotonic start-up into prebiased loads. The default start-up is at VIN equal to 3.8 V. After the device is enabled, the output rises smoothly from 0 V to its regulated voltage. The total operating current is 20 μA (typical) when not switching under no load. When the device is disabled, the supply current is approximately 2 µA (typical). The pulse frequency modulation (PFM) mode maximizes the light load efficiency. These features are extremely beneficial for long battery life time in low-power operation.

The EN pin has an internal pullup current that can be used to adjust the input voltage undervoltage lockout (UVLO) with two external resistors. In addition, the EN pin can be floating for the device to operate with the internal pullup current. This device also has frequency spread spectrum feature, which helps with lowering down EMI noise.

The device has the on-time extension function with a maximum on time of 7 μs (typical). During the low dropout operation, the high-side MOSFET can turn on up to 7 μs, then the high-side MOSFET turns off and the low-side MOSFET turns on with a minimum off time of 140 ns (typical). The device supports the maximum 98% duty cycle.

The device reduces the external component count by integrating the bootstrap circuit. The bias voltage for the integrated high-side MOSFET is supplied by a capacitor between the BST and SW pins. A UVLO circuit monitors the bootstrap capacitor voltage, VBST-SW. When it falls below a preset threshold of 2.5 V (typical), the SW pin is pulled low to recharge the bootstrap capacitor.

Cycle-by-cycle current limiting on the high-side MOSFET protects the device in overload situations and is enhanced by a low-side sourcing current limit, which prevents current runaway. The TPS563300 provides output undervoltage protection (UVP) when the regulated output voltage is lower than 65% of the nominal voltage due to overcurrent being triggered, approximately 256-μs (typical) deglitch time later, both the high-side and low-side MOSFET turn off and the device steps into hiccup mode.

The device minimizes excessive output overvoltage transient by taking advantage of the overvoltage comparator. When the regulated output voltage is greater than 115% of the nominal voltage, the overvoltage comparator is activated, and the high-side MOSFET is turned off and masked from turning on until the output voltage is lower than 110%.

Thermal shutdown disables the device when the die temperature, TJ, exceeds 165°C and enables the device again after TJ decreases below the hysteresis amount of 30°C.