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

9.3.2.6 Enable and Adjusting UVLO

The ENx pin provides electrical on and off control of the device. When the ENx pin voltage exceeds the threshold voltage, the device starts operation. If the ENx pin voltage is pulled below the threshold voltage, the regulator stops switching and enters low Iq state. The ENx pin has an internal pullup current source, allowing the user to float the ENx pin for enabling the device. If an application requires controlling the ENx pin, use open-drain or open-collector output logic to interface with the pin. The device implements internal UVLO circuitry on the VIN pin. The device is disabled when the VIN pin voltage falls below the internal VIN UVLO threshold. The internal VIN UVLO threshold has a hysteresis of 500 mV. If an application requires either a higher UVLO threshold on the VIN pin, or a secondary UVLO on the PVIN, in split rail applications, then the user can configure the ENx pin as shown in Figure 27. When using the external UVLO function, TI recommends to set the hysteresis to be greater than 500 mV.

The ENx pin has a small pullup current Ip which sets the default state of the pin to enable when no external components are connected. The pullup current is also used to control the voltage hysteresis for the UVLO function since it increases by Ih once the ENx pin crosses the enable threshold. The UVLO thresholds can be calculated using Equation 4 and Equation 5.

TPS65283 TPS65283-1 adjustable_VIN_under_voltage_lock_out_slvscl3.gifFigure 27. Adjustable VIN Undervoltage Lockout
Equation 4. TPS65283 TPS65283-1 Eq04_R1_slvscl3.gif

spacer

Equation 5. TPS65283 TPS65283-1 Eq05_R2_slvscl3.gif

where

  • Ih = 3 µA
  • Ip = 3.6 µA
  • VENRISING = 1.2 V
  • VENFALLING = 1.15 V