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TPS22969: GSM module power switching

Giuliano FRANCHETTO
Intellectual 380 points
Part Number: TPS22969

Hi,

We would like to control the power of a GSM module to reduce its power consumption during power-off mode (approx. 30µA)

We looked at the TPS22969, but we have a question about the output capacitance. To reduce the voltage drop during GSM bursts, we have to put capacitors on the VGSM line, as follow:

Will the output capacitance be too big for the TPS22969 to work? Here is how we integrated it in our shematics, with:

  • 3.2V < Vin < 4.2V, 3.7V nominal
  • GSM_CTRL = 0V or 3V

Best regards

  • 0
    TI__Genius 15740 points

    Hi Giuliano,

    The total amount of bulk capacitance you have at the output is about 100uF. The TPS22969 has a rise time in the milliseconds range, and for this amount of capacitance the inrush current will not be an issue for the device.

    For example, if the rise time of the load switch was only 1ms, the expected inrush current from the capacitor would be:

    I = C * dV/dt

    I = 100uF * 3.7V / 1000us

    I = 370mA

    The TPS22969 load switch would have no issues with this amount of current during turn on.

    Thanks,

    Alek Kaknevicius