TIDUF88 October   2024

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Accuracy of Bus Voltage Measuring
      2. 2.2.2 Shunt Current Measuring
      3. 2.2.3 Insulation Impedance Monitor
    3. 2.3 Highlighted Products
      1. 2.3.1 BQ79731-Q1
      2. 2.3.2 TPSI2140-Q1
      3. 2.3.3 ISO7841
      4. 2.3.4 SN6507
      5. 2.3.5 TPS7B6950
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Test Setup
    3. 3.3 Test Results
      1. 3.3.1 Bus Voltage Accuracy
      2. 3.3.2 Current Sensing Accuracy
      3. 3.3.3 Insulation Impedance Accuracy
  10. 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 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author

3.3.3 Insulation Impedance Accuracy

The test setup follows Figure 3-1. A high-voltage DC source provides 1500V to simulate a rack. To verify the current accuracy of the current-sensing circuit, 1500μV (10mA across the 150μΩ shunt) is applied.

Table 3-12 shows the insulation impedance accuracy data. The maximum error of RisoP and RisoN is 6.32% and 3kΩ when RisoP is 50kΩ and RisoN is not connected.

Table 3-12 Insulation Impedance Accuracy Data
RisoP (kΩ) RisoN (kΩ) ERROR OF RisoP ERROR OF RisoN
50 Not connected 6.32% (3kΩ) NA
50 50 –0.83% –1.15%
10000 Not connected –0.67% NA
10000 10000 –0.65% –0.28%
Not connected 50 NA –1.54%
Not connected 10000 NA –0.27%