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TPS24751: TPS24751 easily breaks down when using multiple

JaeKyung Shin
Prodigy 230 points
Part Number: TPS24751

Dear everyone.

I was using TPS24751 very useful.

It is great for me to on/off power and to protect overvoltage.

Recently I designed a board that is consume 30A main power.

Because TPS24751 is very useful, I select TPS24751 for new board too.

But TPS24751 is 10A rated, I divided the main power into three parts. (+12.0V_A, +12.0V_B, +12.V_C)

It work well in the first few time. But it seems to be broken at the end.

When last, It is very hot and look like short DRAIN and GND - very large current consume -.

I want to know why this is the result, and wonder how to prevent this result.

I upload my schematic.

Sincery.

  • 0
    TI__Guru* 96061 points
    Hi Shin,

    Can you please share the parameter values of RSENSE, RSET, RPROG, RIMON and CTIMER of one part.
    Can you provide the input voltage waveform when VIN is inserted at J15 and also snap of layout for one part.

    Best Regards
    Rakesh
  • 0 in reply to Rakesh
    Prodigy 230 points

    Dear Rakesh.

    I am ashamed to use the application schematic in front page of datasheet.

    So I didn't consider the various parameters you mentioned.

    It was designed the same value execpt for Rsense 0.002 --> 0.000 and Cload 470uF --> 560uF

    Now TPS24751 look like broken, I cabling from (+12.0V_IN) to (+12.0V_X).

    I have SMT only one board and the board using others.

    The input voltage waveform will be provided later.

    I paste the layout below.

    L01 - TOP

    L02 = L05 = L07

    L03

    L04 = L06 = L08 = L09

    L10 = L11

    L12 (Bottom)

    Um... It seems very difficult to review layout with picture file.

    If you have any idea, I will aceept it with gratitude.

    Sincery.

  • 0 in reply to JaeKyung Shin
    TI__Guru* 96061 points
    Hi Shin,

    The device monitors the load current through sensed voltage across Rsense resistor.
    Rsense value is very critical for protection. The values given in the front page of datasheet are good for 10A use case.
    Can you test again by placing back 2mOhm for Rsense resistor.

    Best Regards
    Rakesh
  • 0 in reply to Rakesh
    Prodigy 230 points

    Dear Rakesh.

    I designed the circuit like application schematic on front page, but I thought was Figure 48. Simple load switch.

    I don't monitor current and each tps24751 do not pass over 10A except broken on others part on board.

    (It is mesured 1.5A where bypass wire.)

    Although Cgate and Rgate is absent, I thought it would work well on.

    When work well gate voltage is about 25~26V, and when I think breaks, Gate voltage is never change from 0V.

  • 0 in reply to JaeKyung Shin
    TI__Guru* 96061 points
    Hi Shin,

    If you like to use as load switch, please use Cgate and Rgate to limit inrush current while driving large capacitive load 560uF.
    The following app note provides information on the same. www.ti.com/.../slua740.pdf
    Please let me know what type of protection you need for your system?

    Best Regards,
    Rakesh
  • 0 in reply to Rakesh
    Prodigy 230 points
    Dear Rakesh.

    I wired Cgate and Rgate and It look like work well!!!
    It seems that it didn't work because it have larger capactive load (about 3,000uF)

    I really appreciate your help.

    To answer the your last question, I used tps24751 to protection over voltage and to simplfy power switch design.