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TPS3870-Q1: use the RESET pin to drive a N-channel MOSFET

Part Number: TPS3870-Q1

Hi Team,

Our customer needs to control the opening of an N - Channel MOSFET via the RESET pin and would like to understand whether this is possible by connecting the RESET pin to a voltage source via a pull-up resistor?

I have provided the datasheet for the device to serve as a guide but the customer would like to elaborate. In addition, can you also elaborate on the device works in latch mode, i.e. when it doesn't automatically reset the output of the reset pin even if the voltage drops below the threshold value?

Thank you for the help.

Regards,

Marvin

  • Hi Gavin,

    It should be feasible to use the RESET pin of the TPS3870-Q1 (along with pull-up resistor) to control the NFET. Please see App Note below which specifies how to select the value of the pull up resistor for further guidance. Regarding the latch mode, this is achieved by connecting a pull-down resistor to common GND (see image below). When the voltage at the sense pin goes above the voltage threshold then the reset will assert low and will stay low even if the sense voltage drops back down to acceptable levels. To unlatch the device it is recommended to apply a voltage of at least 1.2V to the CT pin (while using series resistance to limit current when unlatch voltage is applied). This will enable the reset signal to de-assert immediately.

    Pull-Up/Down Resistor Selection Guide: www.ti.com/.../slva485.pdf

    Hope this helps, let us know if there is further doubt on the matter.

    Thanks,

    Isa