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BQ24278

hwteam skpp
Prodigy 120 points
Other Parts Discussed in Thread: BQ24278

Hello,

     I have done a Li Ion battery charger using BQ24278. My maximum charger current is 1A.Schematic is attached. The charger is not giving any output. Input is 4.5V. when i check the waveform at SWpin  a low frequency wave is noted. The charger is trying to switch but it is not happening. What could be the probl0572.bq24278.pdfem?

  • 0
    TI__Guru**** 153546 points

    1.  DRV has a minimum capacitor requirement per the d/s.

    2.  SYS needs more capacitance to meet the minimum requirement per the d/s.

    3.  If TS function is not needed, TS must be pulled high to DRV.  This is likely the main problem with the circuit.

    4.  Your VINDPM threshold is 4.5V.  So, the IC will scale back the output current to ensure that the input voltage does not drop below 4.5V.  If there is highly resistive leads/traces from the input source to the IC, then any current

  • 0 in reply to Jeff F
    Prodigy 120 points

    1. I have connected 1uF at DRV pin and tried.

    2. I have increased the SYS capacitance to 47 uF.

    3.TS pin connected to DRV pin and tried

    4. Vin is increased to 5V and tried

    But the system is still not working.