How to eliminate mutual interference between multiplexers in an electrical power measurement switch (PMS)?

In a PMS (Power Management System), when multiple switches (such as different channels in a relay group) operate simultaneously or sequentially, transients generated by one switch can interfere with the drive circuits of other switches and even the load through shared power, shared ground, or spatial coupling, manifesting as false triggering or incorrect status readings. Eliminating mutual interference requires decoupling and isolation design.

Power Decoupling: Provide independent power filtering for each switch driver IC, such as using a PBZ1005B-501Z0T ferrite bead for VCC isolation of each channel.

Ground Isolation: The ground wire of each switch's drive circuit should be routed separately and finally connected to a common ground in a star configuration to avoid common impedance coupling.

Signal Isolation: For control signals, optocouplers (such as TLP281) or digital isolators (such as ADuM1401) can be used to achieve electrical isolation.

Spatially, the switching devices and drive circuits of different channels should be partitioned on the PCB and isolated by ground lines or shielding strips. For high-side switches, use independent charge pumps or isolated power supplies. Software-wise, the operating sequence of multiple switches can be staggered to avoid simultaneous operation. By taking the above measures, the coupling interference voltage between multiple switches can be suppressed to below the logic threshold (such as 0.8V), ensuring that each switch operates independently and reliably.