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BQ24050: BQ24050

eli
Guru 13485 points
Part Number: BQ24050
Other Parts Discussed in Thread: TS3A24159

I have a problem with the item BQ24050DSQR- LI-ION charger.

It is programmed to give 0.54A charging current, but for some reason it is not functioning according to the design.

Sometimes it gives a 0.49A charging current and sometimes 0.035A when plugging a wall adaptor.

What can we do to solve this issue ?

  • 0 in reply to eli
    TI__Guru 71166 points
    Hello
    In the charging condition 490mA when it should be 540mA.
    1.) How are you measuring the charge current?
    2.) What is input voltage at IN pin and output voltage at OUT pin?
    3.) What is voltage at ISET pin, needs to very accurate measurements?

    In the case where charging current is 35mA.
    1.) Battery detect may have tripped, check the output voltage with a scope and look for battery detect square wave.
    2.) OVP may have tripped, check that input voltage is below 6.6V, no spikes or overshoot at start up.
  • 0 in reply to Bill Johns
    Prodigy 60 points
    In the charging condition 490mA when it should be 540mA.
    1.) How are you measuring the charge current?---- I have a DVM connected between the battery pack + and the charging circuit.
    2.) What is input voltage at IN pin and output voltage at OUT pin?-----3.78V
    3.) What is voltage at ISET pin, needs to very accurate measurements?------0.25V

    In the case where charging current is 35mA.
    1.) Battery detect may have tripped, check the output voltage with a scope and look for battery detect square wave.---I don't see any square wave but from what I can tell the output voltage seen is same as the battery voltage, which means that the charger's output is disabled
    2.) OVP may have tripped, check that input voltage is below 6.6V, no spikes or overshoot at start up.-----Checked, don't see any spikes.

    Does ISET2 have to be connected to a host/CPU?


    Best Regards,
  • 0 in reply to yoel ben naim
    Prodigy 60 points

    I looked at it further. It seems that the second problem (35mA) is related to the USB D+, D- detection. 

    I have a USB to UART IC that is connected in parallel to the charger's D+, D-. When I disconnected the USB to UART IC the charger has a constant 0.49A charging current. 

    The D+, D- has a voltage level of 2.8V when the USB to UART IC is connected, and 1.2V when it is disconnected. I am working with an adaptor.

    What can be done to work with them both?

  • 0 in reply to yoel ben naim
    TI__Guru 71166 points
    A couple of thoughts.
    Analog Mux similar to TS3A24159 that will switch the signal lines between the two devices.
    Also the negotiation should be complete after 600mS, possibly disconnect or disable the UART for a short time.
  • 0 in reply to Bill Johns
    Prodigy 60 points

    If I want to work without the USB detect, and output a constant 0.5A current regardless of who is connected to the USB, is it possible?

  • 0 in reply to yoel ben naim
    Prodigy 60 points
    Hi

    I did some changes in the circuit. I disconnected the DP,DN pins of the BQ24050 and shorted them inorder to allow a permanent 0.54A (according to RISET of 1KOHM) regardless of the USB charger type (wall adapter or USB port) . So far it looks that the current is good although not always 0.54. Is this the right way to go for allowing the current to stay at 0.54A?
  • 0 in reply to yoel ben naim
    TI__Guru 71166 points
    Hi
    This looks like a reasonable approach if it meets your requirement