ZHCSJN5A February   2018  – April 2019 TPS2HB50-Q1

ADVANCE INFORMATION for pre-production products; subject to change without notice.  

  1. 特性
  2. 应用
  3. 说明
    1.     简化原理图
  4. 修订历史记录
  5. Device Comparison Table
  6. Pin Configuration and Functions
    1.     Pin Functions
    2. 6.1 Recommended Connections for Unused Pins
  7. Specifications
    1. Table 3. Absolute Maximum Ratings
    2. Table 4. ESD Ratings
    3. Table 5. Recommended Operating Conditions
    4. Table 6. Thermal Information
    5. Table 7. Electrical Characteristics
    6. Table 8. SNS Timing Characteristics
    7. Table 9. Switching Characteristics
  8. Parameter Measurement Information
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Protection Mechanisms
        1. 9.3.1.1 Thermal Shutdown
        2. 9.3.1.2 Current Limit
          1. 9.3.1.2.1 Current Limit Foldback
          2. 9.3.1.2.2 Programmable Current Limit
          3. 9.3.1.2.3 Undervoltage Lockout (UVLO)
          4. 9.3.1.2.4 VBB During Short-to-Ground
        3. 9.3.1.3 Voltage Transients
          1. 9.3.1.3.1 Load Dump
        4. 9.3.1.4 Driving Inductive Loads
        5. 9.3.1.5 Reverse Battery
        6. 9.3.1.6 Fault Event – Timing Diagrams
      2. 9.3.2 Diagnostic Mechanisms
        1. 9.3.2.1 VOUTx Short-to-Battery and Open-Load
          1. 9.3.2.1.1 Detection With Switch Enabled
          2. 9.3.2.1.2 Detection With Switch Disabled
        2. 9.3.2.2 SNS Output
          1. 9.3.2.2.1 RSNS Value
            1. 9.3.2.2.1.1 High Accuracy Load Current Sense
            2. 9.3.2.2.1.2 SNS Output Filter
        3. 9.3.2.3 Fault Indication and SNS Mux
        4. 9.3.2.4 Resistor Sharing
        5. 9.3.2.5 High-Frequency, Low Duty-Cycle Current Sensing
    4. 9.4 Device Functional Modes
      1. 9.4.1 Off
      2. 9.4.2 Standby
      3. 9.4.3 Diagnostic
      4. 9.4.4 Standby Delay
      5. 9.4.5 Active
      6. 9.4.6 Fault
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Ground Protection Network
      2. 10.1.2 Interface With Microcontroller
      3. 10.1.3 I/O Protection
      4. 10.1.4 Inverse Current
      5. 10.1.5 Loss of GND
      6. 10.1.6 Automotive Standards
        1. 10.1.6.1 ISO7637-2
        2. 10.1.6.2 AEC – Q100-012 Short Circuit Reliability
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Thermal Considerations
        2. 10.2.2.2 RILIM Calculation
        3. 10.2.2.3 Diagnostics
          1. 10.2.2.3.1 Selecting the RSNS Value
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    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 相关文档
    2. 13.2 接收文档更新通知
    3. 13.3 社区资源
    4. 13.4 商标
    5. 13.5 静电放电警告
    6. 13.6 术语表
  14. 14机械、封装和可订购信息

Selecting the RSNS Value

Table 16 shows the requirements for the load current sense in this application. The KSNS value is specified for the device and can be found in the Specifications section.

Table 16. RSNS Calculation Parameters

PARAMETER EXAMPLE VALUE
Current Sense Ratio (KSNS) 1500
Largest diagnosable load current 6 A
Smallest diagnosable load current 30 mA
Full-scale ADC voltage 5-V
ADC resolution 10-bit

The load current measurement requirements of 6 A ensures that even in the event of a overcurrent surpassing the device internal 4 A limit, the MCU can register and react by shutting down the TPS2HB50-Q1, while the low level of 30 mA allows for accurate measurement of low load currents.

The RSNS resistor value should be selected such that the largest diagnosable load current puts VSNS at about 95% of the ADC full-scale. With this design, any ADC value above 95% can be considered a fault. Additionally, the RSNS resistor value should ensure that the smallest diagnosable load current does not cause VSNS to fall below 1 LSB of the ADC. With the given example values, a 1.2 kΩ sense resistor satisfies both requirements shown in Table 17.

Table 17. VSNS Calculation

LOAD (A) SENSE RATIO ISNS (mA) RSNS (Ω) VSNS (V) % of 5-V ADC
0.030 1500 0.02 1200 0.024 0.5%
6 1500 4 1200 4.800 96.0%