EMengineer
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Hi everyone,
I have read many useful topics related to this question, but because of the large amount of information and opinions I got confused.
We have internally powered (3.7 VDC) body worn device with CF and BF applied parts and which is charged via USB. Data is send through BT thus the data pins are not used, thus when used on patient there is no connection to other devices.
The device is programmed that it could not be used while charging, thus the risk of mains on SIP/SOP is reduced. Is it possible to cover this with risk by not allowing charging while in use + warning + instructions (operator would be medical personel)?
Although there could be misuse - charging the device on the patient even if the device is not functioning. For example, the operator would charge the device enough to allow one measurement, thus it is not removed from the patient.
My question is about insulation between USB and applied part in such misuse case. Do I understood correctly that USB port shall galvanically be isolated from AP by 2 MOPP's for working voltage (5 VDC) and 1 MOPP for maximum mains voltage (according Fig J.4). In this case the largest a.c and c.d values 1 MOPP for 250 Vrms are - 4 mm c.d and 2,5 mm a.c (when 2 MOPP for 5 VDC are 3,4 mm c.d and 1,6mm a.c). Also dielectric strength test of 1500V should be applied. I hope I did get this part right.
But is it possible to use earlier mentioned risk mitigation measures reduce the potential for such misuse to an acceptable level? Or in any case the galvanic isolation should be used?
I have read many useful topics related to this question, but because of the large amount of information and opinions I got confused.
We have internally powered (3.7 VDC) body worn device with CF and BF applied parts and which is charged via USB. Data is send through BT thus the data pins are not used, thus when used on patient there is no connection to other devices.
The device is programmed that it could not be used while charging, thus the risk of mains on SIP/SOP is reduced. Is it possible to cover this with risk by not allowing charging while in use + warning + instructions (operator would be medical personel)?
Although there could be misuse - charging the device on the patient even if the device is not functioning. For example, the operator would charge the device enough to allow one measurement, thus it is not removed from the patient.
My question is about insulation between USB and applied part in such misuse case. Do I understood correctly that USB port shall galvanically be isolated from AP by 2 MOPP's for working voltage (5 VDC) and 1 MOPP for maximum mains voltage (according Fig J.4). In this case the largest a.c and c.d values 1 MOPP for 250 Vrms are - 4 mm c.d and 2,5 mm a.c (when 2 MOPP for 5 VDC are 3,4 mm c.d and 1,6mm a.c). Also dielectric strength test of 1500V should be applied. I hope I did get this part right.
But is it possible to use earlier mentioned risk mitigation measures reduce the potential for such misuse to an acceptable level? Or in any case the galvanic isolation should be used?