JAJSJE1A July   2021  – December 2021 TPS1HC100-Q1

PRODUCTION DATA  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 説明
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1. 5.1 Recommended Connections for Unused Pins
  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 SNS Timing Characteristics
    7. 6.7 Switching Characteristics
    8. 6.8 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Accurate Current Sense
      2. 8.3.2 Programmable Current Limit
        1. 8.3.2.1 Capacitive Charging
      3. 8.3.3 Inductive-Load Switching-Off Clamp
      4. 8.3.4 Full Protections and Diagnostics
        1. 8.3.4.1  Short-Circuit and Overload Protection
        2. 8.3.4.2  Open-Load and Short-to-Battery Detection
        3. 8.3.4.3  Short-to-Battery Detection
        4. 8.3.4.4  Reverse-Polarity and Battery Protection
        5. 8.3.4.5  Latch-Off Mode
        6. 8.3.4.6  Thermal Protection Behavior
        7. 8.3.4.7  UVLO Protection
        8. 8.3.4.8  Loss of GND Protection
        9. 8.3.4.9  Loss of Power Supply Protection
        10. 8.3.4.10 Reverse Current Protection
        11. 8.3.4.11 Protection for MCU I/Os
      5. 8.3.5 Diagnostic Enable Function
    4. 8.4 Device Functional Modes
      1. 8.4.1 Working Mode
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Dynamically Changing Current Limit
        2. 9.2.2.2 AEC Q100-012 Test Grade A Certification
        3. 9.2.2.3 EMC Transient Disturbances Test
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
      1. 11.2.1 Without a GND Network
      2. 11.2.2 With a GND Network
    3. 11.3 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 サポート・リソース
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

9.2.2 Detailed Design Procedure

To keep maximum voltage on the SNS pin at an acceptable range for the system, calculate the RSNS as in Equation 12. To achieve better current sense accuracy. A 1% accuracy or better resistor is preferred.

Equation 12. (VSNSFH – VHR) × KSNS / ILOAD,max ≤ RSNS ≤ VADC,min × KSNS / ILOAD,min

Table 9-1 Typical Application

Parameter

Value

VDIAG_EN

5 V

ILOAD,max

2 A

ILOAD,min

5 mA

VADC,min

5 mV

VHR

1 V
For this application, an RSNS value of approximately 1 kΩ can be chosen to satisfy the equation requirements.

Equation 13. (5 V – 1 V) × 1040 / 4 A ≤ ≈1 kΩ ≤ 5 mV × 1040 / 5 mA
In other applications, more emphasis can be put on the lower end measurable values, which can increase RSNS. Likewise if the higher currents are of more interest the RSNS can be decreased. Note that the maximum current that can be measured without saturation is 6 A.

Having the maximum SNS voltage scale with the DIAG_EN voltage removes the need for a Zener diode on the SNS pin going to the ADC.

The current limit must be set to an acceptable level, so with the KCL tolerances, the current limit of 4A is chosen. To set the programmable current limit value at 4 A , calculate the RLIM as in Equation 12.

Equation 14. RLIM = KCL / ILIM = 45 / 4 = 11.25 kΩ

For a more accurate current limit estimation with the error tolerances of KCL see the Current Limit Accuracy section and use the graph to estimate the error at each desired current limit value.

TI recommends RPROT = 5 kΩ to ensure the current going into the digital pins (EN, DIAG_EN, LATCH) is limited.

TI recommends a 1-kΩ resistor and 200-V, 0.2-A diode (BAS21 for example) for the GND network.