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TPSI2140-Q1: Avalanche current questions

Barton Tung
Intellectual 1510 points
Part Number: TPSI2140-Q1

Tool/software:

Hi experts,

When i read the datasheet of TPSI2140, I came across the D/S mentioning the Avalanche current of the internal mosfets. The avalanche current tells how much current flows when at avalanche mode. In TPSI2140, the avalanche current is 2mA for 5s and 1mA for 60 seconds. 

I understand that we have avalanche current parameter because of the Hipot test. Regarding to 2mA, usually do we want this parameter as low as possible? Or as high as possible? I believe its low, so that the MOSFET servives better?

In normal operation, said insulation monitoring, I dont think you need the avalanche parameter unless you are passing the Hipot exam, correct?

Thanks and best regards,

Barton

  • 0
    TI__Prodigy 360 points

    Hello Barton,

    Thank you for reaching out with this TPSI2140Q1 inquiry related to Avalanche current rating.

    The Avalanche current specification is relevant whenever the voltage across the S1/S2 pins of TPSI2140Q1 exceeds the avalanche voltage rating (Vava >= 1.3kV). This condition is commonly encountered during the Hipot test as you mentioned.

    While TPSI2140Q1 is in avalanche condition (Vava >= 1.3kV), the device is rated to safely pass an avalanche current of 2mA for 5s or 1mA for 60s. During the avalanche condition, the device can sustain lower avalanche currents for longer periods of time as shown in the avalanche current specification in the datasheet mentioned previously.

    Thank you and let us know if further questions arise.

    Best,

    Hussain

  • 0 in reply to Hussain Alsahhaf
    TI__Prodigy 360 points

    Hello Barton,

    In terms of system level implications related to avalanche current. A higher avalanche current means a higher power dissipation in any series resistor connected to the S1/S2 pins. Care must be taken in specifying these resistors as to not exceed their power or voltage rating, especially during the Hipot test:

    Best,

    Hussain