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LM5050-1: reverse polarity protection for 100V DC motor drive application without reverse current protection

Jan Bock
Expert 3275 points
Part Number: LM5050-1
Other Parts Discussed in Thread: LM74500-Q1

Hi Team, 

can you help with the following customer question: 

We already found LM5050 really suitable for our requirements, but sadly there is an unpleasant feature with this chip, reverse current protection. With motor applications, we need to accept the back emf on the main DC terminals to either charge a battery or dissipate it to protect the system against overshoots in motor regeneration mode.
We hope that Ti has something similar to LM5050 with a 150C/100VDC option but without reverse current protection and only with reverse polarity protection.

Also a custom solution with a small footprint would be appreciated. 

Thanks 

Jan

  • 0
    TI__Guru 57737 points

    Hi Jan,

    For LM5050-1 the reverse polarity protection feature does not work without reverse current blocking feature. So, you cannot disable the reverse current blocking (RCB) feature and still have reverse polarity protection(RPP).

    We do have LM74500-Q1 which has RPP but allows reverse current flow as it does not have RCB functionality. This device is suitable for only 65V DC operation maximum. Unfortunately we do not have any device which can meet your requirement for 100VDC operation. 

  • 0 in reply to Praveen GD
    TI__Expert 3275 points

    Hello Praveen, 

    ok, do you have any other idea how to realize the reverse polarity protection?

    Thanks 

    Jan

  • 0 in reply to Jan Bock
    TI__Guru 57737 points

    Hi Jan,

    You can consider using TPS4811x-Q1 for reverse polarity protection as shown below.

    The above circuit can only work for -30V at the input but for supporting -100V you can us the same circuit by adding a 100V diode in the device GND return path