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TPS274160: A few questions on this device

Roy Hsu
Genius 9180 points
Part Number: TPS274160

Hi Team,

I have a few questions on the TPS274160.

1. If we just use 2 out of the 4 channels of this device, can we do 2A per channel? The datasheet states that 1.35A/channel is possible with all channels on.

 

2. Current limit is adjustable between 0.25A and 4A. Considering a maximum of 1.35A/channel, if we set the current limit at 4A, can this device withstand such a high current? Because it might be loaded with for example, 3A, before hitting the thermal shutdown.

3. We tried to test reverse current protection on the EVM but we found that after removing J11, the EVM doesn't work at all. I have to keep J11 inserted first then remove it later to let the EVM work. Does this seem reasonable to you? Or what's the test procedure of reverse current protection?

Thanks! 

Roy

  • 0
    TI__Genius 16390 points

    Hi Roy,

    Let me try to answer the questions.

    1. If you only use 2 channels out of 4. the capability will be slightly higher since there's no mutual heating from channel to channel, but the capability will be depending on the thermal condition. However, you can parallel the two channel together to achieve higher current capabilities since the equivalent Rdson is halved by paralleling.

    2. The device can withstand higher current for short period of time, but for long term reliable operation, please follow datasheet's recommended DC current value. If 3A is transient, then it should be fine. However, if customer is planned to load the device with 3A for a extended period of time, the device is likely to enter thermal shutdown. If 3A is a typical load value, customer can goes with lower Rdson devices.

    3. It's a strange behavior. Could you try to remove C11 and see if you can get the ground protection work in the first place?

    Regards,

    Yichi

  • 0 in reply to Yichi Zhang.
    TI__Genius 9180 points

    Hi Yichi,

    Thanks for the answers. One follow-up:

    1. Connecting two channels in parallel sounds like a good idea! The original spec is 1.35A/channel so if doing what you suggested, we can expect that it works for at least 2.7A, right?

    Thanks! Roy

  • 0 in reply to Roy Hsu
    TI__Genius 16390 points

    Yes that's correct in theory. In real application, there might be current imbalance during parallel, and the actual max current might be a bit lower.

    Regards,

    Yichi

  • 0 in reply to Yichi Zhang.
    TI__Genius 9180 points

    Hi Yichi,

    Do you have a curve of Δrds(on) over ambient temperature? The value in the datasheet is at Tj = 25C.

    We're asking for this since at Ta = 45C, we found that Δrds(on) between channels might be larger than 6% as we're seeing a 30% difference in current level between the 2 channels.

    Current meter model

    3457A

    3458A

    channel 1

    channel 2

    0.85 A

    1.15 A

    Thanks!

    Roy

  • 0 in reply to Roy Hsu
    TI__Genius 16390 points

    Hi Roy,

    Datasheet does have curves for Rdson vs. temp. It's in Figure 7-10 to Figure 7-14. Please let me know if you have additional questions.

    Regards,

    Yichi