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TPS2492: TPS2492 circuit application.

Mehmet Durna
Prodigy 90 points
Part Number: TPS2492
Other Parts Discussed in Thread: TPS2493

Dear colleagues,

I have two questions about TPS2492. I appreciate if anyone has an experience on them.

1. The datasheet of TPS2492 / TPS2493 gives the current sense level in electrical characteristics table as two different levels: 25mV for power limiting enabled (i.e. Vprog < 4V), and 50mV for no-power limiting function active (i.e. Vprog = 4V). However in the rest of the sections including the design application parts and the design tool (slvc033 Excel design calculator) it is only 50mV used.

2. The current sense level, there is a +/-10% margin on current sense reference 50mV or 25mV. I assume this is the production deviation, and is nearly fixed when the part is selected, and the current limit is than dependent only on the temperature effects and the sense resistor tolerances. Could you please confirm this? I appreciate for your helps,

Best regards,

Mehmet DURNA

  • 0
    TI__Guru** 105791 points

    Hi Mehmet,

    Thanks for reaching out!

    1A) The current limit threshold during startup is 25mV. After reaching the steady state, the current limit threshold becomes 50mV. 

    The sense resistor to set the overload limit should be based on 50mV threshold.

    2A) The +/-10% variation in the current limit threshold includes process variation, voltage 9 V ≤ VVCC ≤ 80 V and temperature -40°C ≤ TJ ≤ 125°C. It does not include the sense resistor tolerance.

    Best Regards, Rakesh

  • 0 in reply to Rakesh
    Prodigy 90 points

    Dear Rakesh,

    Many thanks for your response. It is very helpful. May I ask you an additional question so I can feel more confidence on choosing my components.

    For current limit threshold, the Figure 2 of datasheet (*) gives me a way to interpolate the variation at my temperature interval. For supply voltage dependence (my operation is at 27V - 29V), I could not find an explicit data on the datasheet. The most closest one is Figure 12, however it is a little bit obscure for me. Could you please explain how to use it?

    Best regards,

    (*) www.ti.com/.../tps2493.pdf

  • +1 in reply to Mehmet Durna
    TI__Guru** 105791 points

    Hi Mehmet,

    Figure 12 shows the variation with respect to supply voltage. The variation is very less with the supply voltage. 

    We recommend to consider +/-10% variation on the current limit threshold while designing as it also considers the process variation.

    Best Regards, Rakesh

  • 0 in reply to Rakesh
    Prodigy 90 points

    Dear Rakesh,

    Many thanks for your helps.

    Best regards,

    Mehmet