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TLVM13660: EMI Input Filter Design

GAURAV JOSHI
Prodigy 10 points
Part Number: TLVM13660
Other Parts Discussed in Thread: TPS2663, TPS2660

Hello Everyone,
We are designing a PLC for an industrial automation application.
The PLC takes in input from a general purpose industrial 24VDC Power Supply (which is not in scope of our supply ).
The Power Supply could be industrial grade or not, could be EMI/EMC Compliant or not and the output of the Power Supply could be filtered, regulated, absorb surge or not. In such a condition, what sort of protection should we provide at the input side of our circuit. The input then drives a DC-DC converted which is designed as per TI schematic reference. However, the 24VDC input would also be used for driving IOs of the power supply with the help of a ADR74413r.
Can someone please recommend an input side circuit, which shall convert unfiltered 24VDC to filtered 24VDC supply, including something for ESD, EFT & transient surge protection (including those in typical industrial environment ).
Regards,
Gaurav

  • 0
    TI__Guru 50120 points

    Hello Gaurav,

    It sounds like you are asking more about input power path protection circuit which may be e-fuse, diode controller, etc , not related to the DC/DC SMPS converter.

    This thread will be assigned to the LP-PS org and an appropriate engineer will look into answer this question.

    Regards,

    Jimmy

  • 0 in reply to Jimmy Hua
    TI__Guru** 102551 points

    Hello Gaurav,

    TPS2660 and TPS2663 are suitable eFuse devices to use at the system input to handle surge events.

    Please refer application note  https://www.ti.com/lit/an/slva833d/slva833d.pdf

    Best Regards,

    Rakesh

  • 0 in reply to Rakesh
    Prodigy 10 points

    Hello Rakesh,

    Thanks for the response.

    But clear my understanding. As per the schematic for efuse TPS2660 there is a SMCJ28CA transil shown, which shall absorb the surge transient from going to the TPS2660.

    I fear, wont the SMCJ28CA itself have to absorb this trabsient and wont it damage the transil.

  • 0 in reply to GAURAV JOSHI
    TI__Guru** 102551 points

    Hello Gaurav,

    The energy content in surge event is not that high. +/-500V, 2Ω surge event can be easily handled by SMCJ28CA diode. You may need to increase TVS diode size (SMD type) if you aim for high level of surge 

    which one you are targeting ?

    https://www.ti.com/lit/an/slva711/slva711.pdf 

    BR,

    Rakesh

  • 0 in reply to Rakesh
    Prodigy 10 points

    Hello Rakesh,

    Once again, I appreciate the prompt reply.

    Talking about the voltage levels, the equipment that we are developing is an industrial PLC, with an inbuilt HMI. It is expected to be used in an industrial enviroment, ideally mounted in an electrical panel, driven from a SMPS based AC/DC power supply 24VDC ( common supply across all 24VDC equipment used in the panel ), which shall ideally be complient with EMI/EMC standard. However, since we wouldn't be specifying any specific power supply or supplying any power supply with our equipment, we need to design it such that it on its own shall withstand the surge, ESD & EFT. Meaning we need to get our PLC tested singularly for EMI/EMC. Now since, inside a control panel, all cables ( power / signals ) run in parallel, I believe a 4KV / 2000A spike is what we should test with. Its like the worst cass scenario. 

    Can you suggest a schematic for the Input side EMI filters, capacitors & Surge protection device. The rated current of our device is around 2A at 24VDC.

    Regards,

    Gaurav

  • 0 in reply to GAURAV JOSHI
    TI__Guru** 102551 points

    You may need some passive filters at the input to support 4kv. We don't have reference design for the same. Let us know if you have any questions on the device

    Best regards 

    Rakesh