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TPS2663: TPS26631 priority power MUX 48Vdc of two 48 VDC supplies

Fernando Amadeu
Prodigy 30 points
Part Number: TPS2663

Tool/software:

I want to use two TPS26631 eFUSEs for priority power multiplexing of two 48 VDC supplies.

In section 10.3.2 of the datasheet it is stated the following: "TPS2663x devices provide a simple solution for priority power multiplexing needs."

How should resistors R8 and Q5 be calculated? I have the BSS139 NMOS with Vgs(th) of 1.4V and Vds of 250V, does this model meet the requirements?

Is the connection of the input sources correct? If there is inversion in the secondary source, would the eFuse be protected?

Tks

  • +1
    TI__Guru** 105361 points

    Hi,

    Circuit function: Under normal operation, if VIN_MAIN is present, the primary eFuse turns on. When the primary eFuse is operating, the dVdT(Primary eFuse) is typically 4.17 V.  The voltage across R8 will be 4.17V-Vth(Q5) which is higher than OVP threshold of 1.2V. This keeps the internal FET of the secondary eFuse disabled. You can select R8 in the order of 100k to 1000k to minimize the shunt current from VIN_AUX

    Drain of Q5 is connected to VIN_AUX so the Vds rating for Q5 should be max battery voltage (60V) you can select 80V if margin is required.

    Configuration looks fine to me,

    The reverse polarity function still works. However, you need to select 100V FETs for Q1 and Q3 to support that.

    BR,

    Rakesh