TIDUFG5 December   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Insulation Monitoring
    2. 1.2 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 TIDA-010985 Overview
      2. 2.2.2 Solving for the Unknown Isolation Resistances
      3. 2.2.3 Addressing Large Time Constant Cases
      4. 2.2.4 Prediction Algorithms
      5. 2.2.5 Understanding Error Sources
    3. 2.3 Highlighted Products
      1. 2.3.1 LP-MSPM0G3507
      2. 2.3.2 TPSI2240-Q1
      3. 2.3.3 RES60A-Q1
      4. 2.3.4 TLV9002-Q1
      5. 2.3.5 TPSM33620-Q1
      6. 2.3.6 TPS7A2033
      7. 2.3.7 ISOW1044
      8. 2.3.8 TSM24CA
      9. 2.3.9 TLV431B
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Software
    3. 3.3 Test Setup
      1. 3.3.1 Hardware Test Setup
      2. 3.3.2 Software Test Setup
    4. 3.4 Test Results
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
      3. 4.1.3 PCB Layout Recommendations
        1. 4.1.3.1 Layout Prints
    2. 4.2 Tools and Software [Required Topic]
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Authors

1 System Description

High-voltage (HV) DC systems show accelerated adoption across multiple end equipment applications including energy storage systems, data centers, solar inverters, and DC fast chargers. The typical DC voltage for these applications ranges from 150V to 1000V. Larger energy storage systems operate at voltages up to 1500V.

User protection represents an important design consideration in these HV DC systems. All HV parts of the system receive electrical isolation from PE through high-omic paths (typically in the high MΩ range). The insulation limits the maximum leakage current. International standards (for example, UL 2231-2, IEC 61851-23 for EV charging) require that leakage current remain limited to 10mA (that is, 100Ω/V) to avoid personal injury from contact with the system. IEC 61851-23 specifies a safe isolation rating when the leakage measures less than 2mA (500Ω/V). Table 1-1 shows the insulation monitoring device (IMD) key thresholds. Figure 1-1 shows that the IMD monitors insulation resistance and reports faults to the main controller when the insulation resistance becomes insufficient. The main system controller initiates a safe shutdown sequence following a fault. These IMDs operate continuously at a low frequency of 1Hz to 2Hz because insulation changes occur slowly.

TIDA-010985 Insulation Monitoring Device in DC Unearthed Distribution Systems Figure 1-1 Insulation Monitoring Device in DC Unearthed Distribution Systems
Table 1-1 IMD Key Thresholds from IEC and UL Standards
STATUS Ω/V LEAKAGE CURRENT 800V VBus 1000V VBus
Warning 500 2mA 400kΩ 500kΩ
Fault 100 10mA 80kΩ 100kΩ