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BQ25504EVM-674: Does not draw current

Joshua Vincent
Prodigy 30 points

Part Number: BQ25504EVM-674

Hello,

I am testing the BQ25504EVM-674 as per pages 5 - 9 of the datasheet: .

I connected a 20 Ohm resistor in series with the input voltage source. The voltage source is set to 1.0 V. I inserted a 10 kOhm resistor across STOR and GROUND. I simulated a battery as per page 3 of the datasheet and connected it to BAT and GND.

During my tests, I noticed that the boost converter is not drawing any current. According to the specs, the boost converter should draw around 200 mA of current. In addition, VSTOR is not charging. Finally, BAT_OK always has a negative voltage of around -65 mV. Why?

  • 0
    TI__Mastermind 20570 points
    Joshua,
    First, can you please verify all the jumper setting to make sure the device is in normal operation?
    There are several test from page 5 to 9, which are the test that you are having issue? or are you having issue on all of them?
    Please attach scope waveform on the tests you are having issue with.
  • 0 in reply to Jing Zou
    Prodigy 30 points
    What do you mean by jumper settings? Are you referring to the shunt on JP1? If that is the case, the shunt bridges R-DIV and OCS.
    Yes. The boost converter does not draw current for all tests.
    I do not have an oscilloscope. I only have multimeters, which I use to monitor the voltage at each point.

    Thank you,
    Joshua Vincent
  • 0 in reply to Joshua Vincent
    TI__Guru**** 165886 points
    At what voltage is the power supply of your simulated battery? It needs to lower than the bq25504's VBAT_OV setting. If you remove the simulated battery and/or the 10kohm resistor, do you see a voltage at VSTOR and VBAT?
  • 0 in reply to Jeff F
    Prodigy 30 points
    The voltage on the power supply is 2.5 V. The BQ25504 EVM has a preset VBAT_OV of 3.1 V. If I remove either the simulated battery or the and/or the 10kOhm resistor, I do not see a voltage on either VSTOR or VBAT.