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TLV62568: TLV62568

ANURAJ NK
Intellectual 510 points
Part Number: TLV62568

Hi,

    In buck converter TLV62568, if the EN pin is connected to ground, the output will be disabled,i.e 0V.

Hope this is doing by setting the upper FET to OFF and bottom FET is ON condition. Can you confirm.

Regards

Anuraj NK 

   

  • 0
    TI__Expert 3465 points
    Hello Anuraj,

    when the device is disabled both Highside and lowside mosfets are turned off, hence the switching node is in high impedance state.
  • 0 in reply to Emmanuel Granatello
    Intellectual 510 points
    Hi Emmanuel,

    I am looking for procedure to validate the Rds(on) value mentioned in the datasheet.


    High-side FET on resistance: I will set both input and output as same, so that High side FET will be continuously ON and bottom Fet will be OFF. I will force current to SW pin and measure the volatge. Vin - measured volatge/ force current will be the Rds(on)

    Low-side FET on resistance : I have to switch ON only bottom FET to do this test.Can you tell me, What is the procedure to turn on only botton FET and measure the Rds(on) ?


    Regards
    Anuraj NK
  • 0 in reply to ANURAJ NK
    TI__Expert 3465 points
    Hello Anuraj,

    your method may seem correct, but introduces many measurements errors.

    In principle, what I would do is to play with the FB pin because:
    case 1 - Vfb>Vref -> the control loop "thinks" there is too much energy at Vout and tries to discharge the Cout = LS ON & HS OFF
    case 2 - Vfb<Vref -> the control loop "thinks" there is too less energy at Vout and tries to charge the Cout = LS OFF & HS ON

    Hence in both cases you must remove the inductor (open the loop and avoid switching current flows) and force a DC current at SW pin. Pay attention to two things, reference pin and the verse of the forced current current:
    case 1 - positive verse from SW to GND
    case 2 - positive verse from VIN to SW

    if you invert the verse of the current, this will flow in the FET's backdiode, and you'll measure around 0.7.

    Another point is the current limit: do not exceed is in any of the cases, otherwise you'll get a fet turn off.

    I repeat, this procedure should work in principle, I have never tried it on the TLV62568.