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TIDA-00366: Overcurrent vs short circuit protection

Mohana Krishnan M
Prodigy 215 points
Part Number: TIDA-00366
Other Parts Discussed in Thread: TLC372, CD4044B, TLV1701

Dear Team,

In the TIDA-00366 design, overcurrent protection is implemented through comparator circuit.

It is also mentioned that short circuit protection is also incorporated through the circuit. Is there any specific details on short circuit protection for the design (or) it is combined with overcurrent protection?

Kindly support.

Regards,

Mohana Krishnan M

  • 0
    TI__Prodigy 640 points

    Hi Mohana Krishnan,

    Thanks for the question. The short circuit protection is also implemented by the overcurrent protection circuit(TLC372) - short-circuit is an extension of overcurrent and OVERLOAD signal is used to disable the gate drivers by pulling the ENABLE pins LOW in the event of a short-circuit.

    Regards

    Siva

  • 0 in reply to Siva Mohan
    Prodigy 215 points

    Hi SIva,

    Is it possible to latch the OVERLOAD signal in hardware itself and release the latch using a signal from MCU?

    Regards,

    Mohana Krishnan M

  • 0 in reply to Mohana Krishnan M
    TI__Prodigy 640 points

    Hi Mohana Krishnan,

    It is not possible to latch the OVERLOAD signal in existing hardware - TRIP signal is used to latch OVERLOAD signal using software.

    Regards

    Siva

  • 0 in reply to Siva Mohan
    Prodigy 215 points

    Hi Siva,

    I Could see from schematics that there is no hardware latch in existing one. I was expecting to get know what changes need to be made in hardware to achieve the same in this.

    Also, the positive and negative reference for 3 phases are generated separately (U phase - R4, R11, R19; V phase - R25, R32, R40; W phase - R46, R53, R61). Could we generate the reference with single potential divider and use the same for all three? Why three separate dividers are used? Is there any special reason for this consideration?

    Regards,

    Mohana Krishnan M

  • 0 in reply to Mohana Krishnan M
    TI__Prodigy 640 points

    Hi Mohana Krishnan,

    The OVERLOAD signal can latched using a S-R latch like CD4044B - OVERLOAD will be R-input and reset from MCU will be S-input. The latch output will be the input to the 3-terminal AND gate in the design. This way the OVERLOAD fault gets latched and can be cleared by pulling reset signal from MCU LOW - please note that reset signal from MCU needs to be HIGH for fault to be latched. 

    Yes, you can use single potential divider for all three phases. Three dividers were used in this design to ease layout and routing.

    Regards

    Siva

  • 0 in reply to Siva Mohan
    Prodigy 215 points

    Hi Siva,

    Thanks for your input. Is there any specific reason for zero ohms at the output of every comparator? I am not able to simulate it without zero ohms.

    What is the purpose of this in practical circuit?

  • 0 in reply to Mohana Krishnan M
    TI__Prodigy 640 points

    Hi Mohana Krishnan,

    The  zero ohm resistors are place holder resistors just in case there needed to be a non-zero resistor in that location.

    Regarding the simulation, can you please provide more information on the simulation platform, circuit etc.,

    Regards
    Siva

  • 0 in reply to Siva Mohan
    Prodigy 215 points

    Please find the simulation attached.OCP.TSC

  • 0 in reply to Mohana Krishnan M
    TI__Prodigy 640 points

    Hi Mohana Krishnan,

    I simulated the file with and without the zero ohm resistors at output of TLV1701 and found the results were same in both cases. What issue did you face when you simulated without the zero ohm resistors?

    Regards

    Siva