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TPS3808: How to change the detection voltage

user1536405
Prodigy 30 points
Part Number: TPS3808

Hi expert,

I have a question about TPS3808.
Is it possible to change the detected voltage using the Fixed Voltage Version of the TPS3808?

The Fixed Voltage Version in the Functional Block Diagram contains a 4MΩ resistor between the SENSE and GND pins.
Is it possible to change the detection voltage by placing a resistor between the power supply and the SENSE pin?

For example, in the case of TPS3808G33, it can be calculated that R1 is about 3.47MΩ and R2 is about 0.53MΩ, which are connected to the SENSE pin and GND pin.
If I want to detect 4V, should I put a resistor of about 1.23MΩ between the power supply and the SENSE pin?

Best regards,

  • +1
    TI__Mastermind 19370 points

    Hi,

    If you want to change the threshold on TPS3808 with external resistors, use the TPS3808G01 which is what we call the "adjustable variant"

    The G33 has a internal resistor ladder what increases Input sense current to the uA level which is not good for external resistors when looking at overall accuracy.

    The adjustable variant has nA level of input sense current that allows for easier threshold setting.

    The way to set it with the adjustable G01 is below

    Internal threshold = input voltage ( R2/ (R1 + R2)) where R1 and R2 are the voltage divider into the sense pin and R2 is the resistor between sense and GND.