This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS546A24A: Can TPS546A24A sink it's full spec current as well as source it. Bi-polar bridge application

Part Number: TPS546A24A
Other Parts Discussed in Thread: TPS546D24A, TPS546B24A, TPS546B24AEVM

I would like to know if the TPS546A24A can sink as well as source it's specified max current (10A) from a pre-biased load once slow start is complete. I was thinking of using two in a bridge configuration. Would be for bi-polar Peltier control.


    The TPS546x24A devices have a negative current limit, which is fixed and not user programmable, and the under-current response to turn-off the low-side FET and remain free-wheeling for the remainder of the switching cycle is not programmable.

    The typical under current limit ratings for the devices are:

    TPS546D24A: -20A

    TPS546B24A: -10A

    TPS546A24A: -10A

    Because the negative current limit terminates the current pulse, it is a valley current limit, so the DC sinking current will be less negative than the current limit, so the inductor ripple current will reduce the negative current limit and the amount of current that the TPS546x24A devices can sink.

  • Hi,

    Thanks for the reply. This may be okay for our application as we don't need the full 10A sink, maybe half that.

    There are many devices that have negative current limit much lower than the figure you suggest, even fairly high current sourcing ones.

    Often hard to find the figures in the datasheets as often not mentioned.

    Will have to give an evaluation board a test.


    I am glad that we were able to assist you.

    The TPS546A24A negative current limit is listed in its datasheet Electrical Specifications Table on page 10.

    Unfortunately, we do not currently have a TPS546A24A EVM available, but you can use a TPS546B24AEVM which has the same negative current limit as the TPS546A24A.  To convert the 2-phase TPS546B24AEVM into single phase mode:

    1) Remove R15_P1 to separate the U1 device's VSHARE voltage from the U2 device's VSHARE

    2) Populate R18_P1 to short the U1 device's MSEL2 pin to AGND to configure U2 as a single phase.

    If you would like to better emulate a TPS546A24A in your evaluation, you can populate R18_P1 with a 21.5kOhm resistor to select the 10A Over Current Warning and 14A Over Current Fault levels to match the TPS546A24A's values.