ZHCU837 December   2021

 

  1.   说明
  2.   资源
  3.   特性
  4.   应用
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
      1.      10
    2. 2.2 Highlighted Products
      1. 2.2.1 DRV5056
      2. 2.2.2 DRV5032
      3. 2.2.3 TPS709
      4. 2.2.4 SN74HCS00
      5. 2.2.5 TPS22917
      6. 2.2.6 SN74AUP1G00
      7. 2.2.7 TLV9061
    3. 2.3 Design Considerations
      1. 2.3.1 Design Hardware Implementation
        1. 2.3.1.1 Hall-Effect Switches
          1. 2.3.1.1.1 U1 Wake-Up Sensor Configuration
          2. 2.3.1.1.2 U2 Stray-Field Sensor Configuration
          3. 2.3.1.1.3 U3 and U4 Tamper Sensor Configuration
          4. 2.3.1.1.4 Hall Switch Placement
            1. 2.3.1.1.4.1 Placement of U1 and U2 Sensors
              1. 2.3.1.1.4.1.1 U1 and U2 Magnetic Flux Density Estimation Results
            2. 2.3.1.1.4.2 Placement of U3 and U4 Hall Switches
              1. 2.3.1.1.4.2.1 U3 and U4 Magnetic Flux Density Estimation Results
          5. 2.3.1.1.5 Using Logic Gates to Combine Outputs from Hall-Effect Switches
        2. 2.3.1.2 Linear Hall-Effect Sensor Output
          1. 2.3.1.2.1 DRV5056 Power
          2. 2.3.1.2.2 DRV5056 Output Voltage
          3. 2.3.1.2.3 DRV5056 Placement
        3. 2.3.1.3 Power Supply
        4. 2.3.1.4 Transistor Circuit for Creating High-Voltage Enable Signal
      2. 2.3.2 Alternative Implementations
        1. 2.3.2.1 Replacing 20-Hz Tamper Switches With 5-Hz Tamper Switches
        2. 2.3.2.2 Using Shielding to Replace Tamper Switches and Stray Field Switch
        3. 2.3.2.3 Replacing Hall-Based Wake-Up Alert Function With a Mechanical Switch
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
      1. 3.1.1 Installation and Demonstration Instructions
      2. 3.1.2 Test Points and LEDs
      3. 3.1.3 Configuration Options
        1. 3.1.3.1 Disabling Hall-Effect Switches
        2. 3.1.3.2 Configuring Hardware for Standalone Mode or Connection to External Systems
    2. 3.2 Test Setup
      1. 3.2.1 Output Voltage Accuracy Testing
      2. 3.2.2 Magnetic Tampering Testing
      3. 3.2.3 Current Consumption Testing
    3. 3.3 Test Results
      1. 3.3.1 Output Voltage Accuracy Pre-Calibration Results
      2. 3.3.2 Output Voltage Accuracy Post-Calibration Results
      3. 3.3.3 Magnetic Tampering Results
      4. 3.3.4 Current Consumption Results
  9. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 支持资源
    5. 4.5 Trademarks
2.3.1.1.4.1.1 U1 and U2 Magnetic Flux Density Estimation Results

The magnetic flux density detected at switches U1 and U2 were simulated to determine appropriate placement of the Hall-effect sensors. For simulation, the distance measurements are done with respect to the sensing element to the magnet since the simulation tool does not automatically consider the location of the sensing element within the device.

Figure 2-16 shows a plot of the simulation results for the U1 and U2 sensors. If the sensed magnetic flux density of U1 is above the U1 OUT LOW horizontal line (BOP,MAX) in the results, the output of U1 is assured to be low. If the sensed magnetic flux density of U1 is below the U1 OUT HIGH horizontal line (BRP,MIN) in the results, the output of U1 is assured to be high. Similarly, if the sensed magnetic flux density of U2 is below the U2 OUT LOW horizontal line (BOP,MIN) in the results and it is powered, the output of U2 is assured to be low. If the sensed magnetic flux density of U2 is above the U2 OUT HIGH horizontal line (BRP,MAX) in the results and it is powered, the output of U2 is assured to be high.

Figure 2-16 Simulated Magnetic Flux Density Present at U1 and U2

In the results, notice that the output of U1 is not ensured to be low until the trigger is pressed at least 0.3 mm. The output on U2; however, is always asserted low as long as it is powered. If the output of U1 is not asserted low, U2 is not powered.