Application challenge
- EV and hybrid platforms contain multiple high-voltage modules that must be monitored before and during operation.
- The insulation-measurement path needs a switch with very low leakage, repeatable isolation, stable capacitance and long mechanical life.
- Semiconductor isolation devices may introduce temperature-dependent capacitance or leakage; conventional electromechanical relays may be larger and slower for dense monitoring boards.
Design approach
- Use the relay to connect the insulation-measurement network only during the measurement window, then return the high-voltage bus to its normal isolated state.
- Keep creepage, clearance and PCB contamination control consistent with the final bus voltage and pollution degree.
- For 800 V and higher platforms, select the relay by withstand voltage, insulation resistance and leakage-current budget rather than by nominal voltage alone.
- Where the measurement channel is used as a safety diagnostic, validate the complete circuit under humidity, temperature, surge and aging conditions.
Engineering caution: catalog ratings are component-level references. For high-voltage, medical, EV, PV or ATE systems, verify creepage, clearance, leakage, thermal rise, EMC and lifetime in the finished equipment.
Related MiRelay series
HVR high-voltage reed relays are suitable for high isolation paths; SIP-HV is useful where the board area is limited and the required switching voltage is lower.
Series mentioned: HVR high voltage reed relays, SIP-HV high voltage SIP reed relays