ARM system board external USB device burned industrial PC motherboard occurrence, unable to boot

Problem description: ARM system board for a USB device power supply and USB direct motherboard, motherboard USB port signal ground and ARM system board power supply switching power supply dc together, or the occurrence of the abnormal motherboard USB port directly burned
the condition of the
Objective: to find out the real reason for motherboard USB port and the occurrence of the fire, how to deal with the earthing can truly put an end to the mainboard burned
the condition of the
Problems of record:
A: the situation of over-voltage caused the mainboard burned (ARM system board normal 12 v power supply)
1, the ARM on the system board using 1 a self recovery fuse and SMBJ15CA TVS diode, ARM system board GND and chassis PGND is no electrical connection
2, the motherboard USB port signal ground with ARM board to power supply switch power supply, dc were
2, there are a few staff to meet the 24 v switching power supply, TVS diode burned, the occurrence of the mainboard burned (whether electric mainboard or not electricity, will burn)
Can you tell me the motherboard specific what is the cause of the fire, dealing with grounding to avoid such things
Need to use ARM board power supply (USB peripherals, because USB peripherals far distance mainboard, motherboard USB port power supply instability)
2: cause the mainboard burned cases in normal use
1, will appear in the process of normal use USB port or abnormal occurrence of the abnormal situation
2, a serial port connection industrial control ARM system board have two road, a serial port GND is total to
3, the rest of the interface, in addition to the graphics card, no other interface
Excuse me this kind of situation may be the cause of the burning, need to how to deal with the external power supply peripherals to dc with industrial control signal to issue

3: if you use the interface segregation, whether the USB port and serial port needs to be isolated, whether there are other viable option, thank you

CodePudding user response:

Still hope the great god give guidance, thank you very much

CodePudding user response:

CodePudding user response:

Have a great spirit to help solve, thank you

CodePudding user response:

In this electrical isolation requirements higher, the proposed network interface