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TPS63001: Single cell lipo cutoff

Bas Vuyk
Prodigy 90 points
Part Number: TPS63001

I want to implement the TPS63001 in my design with a single cell limo. As seen in the datasheet the VINA pin can be used to shut down the converter once the voltage drops below 1.6V. This means that a 1/2 voltage divider should be enough to disable the converter at 3.2V. But how can I implement this with the capacitor. Currently my design looks like this:

  • 0
    TI__Expert 8420 points
    If VINA drops below 1.6V, which is in the range of the undervoltage lockout threshold, the device would not shut down, it would automatically try to restart .

    If you want to disable the converter at 3.2V, I would recommend to implement the circuitry only for EN pin not for VINA and PS/SYNC pins
  • 0 in reply to Sabrina
    Prodigy 90 points

    You're right, I've totally overlooked that. So something like this would be ok?

  • 0 in reply to Bas Vuyk
    TI__Expert 8420 points
    please take a look at the EN pin high and low threshold, the current circuit would not disable the converter at 3.2V.
  • 0 in reply to Sabrina
    Prodigy 90 points
    So if I'm correct the voltage should drop below 0.4V for the EN pin, but since the High voltage is 1.2V how will the controller be enabled again. Because 0,4v from a resistor divider would mean a 8/1 ratio, so 1,2*8 is 9,6v, which is not gonna work from a single limo cell. Or am I overlooking something here?
  • 0 in reply to Bas Vuyk
    TI__Expert 8420 points
    Right, I guess you would need to think of another solution of disabling the converter when not needed. I think a simple resistive divider would not be reliable in this case.
    What are the conditions/parameter decidint weather to enable or disable the converter?
  • 0 in reply to Sabrina
    Prodigy 90 points

    Since the converter will be powered by a single cell Lipo, ideally the cutoff would be between 3.0-3.3V. But I've found an alternative solution. I'm planning on using an APX809S, this will monitor the voltage and cutoff a 3.1V. This ic will be connected to the EN pin of the TPS63001, providing a low signal when in reset.