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TPS3700: if the voltage has variation during operation, whether the devices has problems?

Frank Xiao
Genius 12055 points
Part Number: TPS3700

Hi team,

My customer wants to use the TPS3700 in their system. i have some questions want to check with you.

1. The supply and monitor voltage are the same(12V). if the voltage has variation during operation, whether the devices has problems? From the datasheet, it seems to be fine.

2.The UV is 10.8V, OV is 13.2V.

The internal reference voltage is only 0.4V. My customer has concern about so low reference voltage, whether it has risks? for the divider resistor value, do you have some suggestions? Do we have some higher reference devices?

whether the excel result is ok?

Feel free to let me know when you have other recommendations.

Thanks.

 

  • 0
    TI__Genius 12630 points
    Frank,

    1. If the voltage have variation during operation, it is important that VDD always remains above recommended operating VDD_min and below the VDD_max. The resistor dividers should be set so that when the voltage variation reaches a desired threshold, the VIT- and VIT+ reach the internal worst case reference voltage. There is no issue when designed correctly.

    2. The only issue when monitoring higher voltages is the total system supply current increases because current flows through the resistor divider to set the proper thresholds. Because the inputs are going to an internal comparator, the input impedance is very high and the sense currents (I_INA+ and I_INB-) are very low. Using large resistor values (total resistance of resistor divider should be above 1Mohm) will also help minimize the additional current required by the resistor divider.

    3. The Excel calculator simply implements the design equations in the datasheet and attempts to factor in device accuracy to show potential worst case situations. Use the Excel calculator as a supplement tool but please be sure to test as well. When you choose your desired thresholds or resistor values, please also verify with section 8.2.2.1 Resistor Divider Selection of the datasheet.

    Please let me know if you need any assistance or need a schematic review when the resistor values and/or desired thresholds and system requirements are chosen. We can help you and the customer arrive at the correct solution.

    -Michael