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BQ24190: BQ24190 Heat problem

Part Number: BQ24190

Dear TI Team.

I have a heating problem during the TEST for BQ24190.

When the PCB is made and the battery is connected directly, the temperature of the BQ24190 goes up to 65 degrees.

To check the charging current, disconnect the + terminal of the battery and connect the current meter to operate the BQ24190.

 It drops to about 45 degrees. Is it possible to determine what the cause is?

Thanks.

  • Hi Chun,

    Can you provide some more information to debug this device? I would like the following:

    • Layout file of your PCB
    • Desired charging current
    • Measured current during your test
    • VBUS input voltage
    • Battery voltage 

    Thanks,

    John

  • Dear John.

    Thank you for answering.

    • Layout file of your PCB 

            Top

            

    2nd

    1. Desired Charging Current : Norminal 1.5A (0.5C), Sometimes we need to 3A(1C). Battery specification : 3.75V Li-ion, 3000mA/h
    2. Mesured Current during testing : about 1.3A to 1.7A , most of 1.5A
    3. VBUS input voltage : We have already used over voltage protection circuit. It is typical 5V. (4.4V to 5.7V)

    Thanks.

    
    
  • Hi Chun,

    Thanks for the layout. Could I also have the following:

    1. A schematic, to help understand the layout and I would like to see your over voltage protection circuit.

    2. Could you mark on your layout where the connections were made during the two testing states?

    Thanks,
    John
  • 1. A schematic, to help understand the layout and I would like to see your over voltage protection circuit.

    2. Could you mark on your layout where the connections were made during the two testing states?

    --> After connecting battery connector to CON301 in the circuit diagram, we disconnected the cable of battery + and measured

         it by connecting it with current meter.

    Thanks.

  • Hi Chun,

    I noticed that schematic was marked confidential and wanted to remind you that this is a public forum, if that;s something you do not want to share.

    From your schematic, I looked up the inductor you chose and the rated current is said to be 1.4A. This may be an issue at higher charging currents. Could you do the following:

    1. Run the same set of tests, but with a charging current of 1A.
    2. What is the battery voltage during these tests (TP15)?
    3. How are you measuring the temperature of the IC?

    Thanks,
    John
  • Dear John.

    1. Run the same set of tests, but with a charging current of 1A.
    --> 2012 size inductor specifications use 3A parts
    As shown in the circuit diagram, the charging current is 178 ohm (3A, 1C) for Ilim HW VALUE, and REGISTER is set for SW of 2A.
    2. What is the battery voltage during these tests (TP15)?
    --> Battery voltage is usually 3.7 ~ 3.8V when charging.

    3. How are you measuring the temperature of the IC?
    --> The surface temperature was measured with a contact thermometer.

    Thanks.
  • Hi Chun,

    What is the temperature of the battery and the inductor for both tests?

    I want to confirm, you are charging at 2A?

    Is the input power the same for both tests?

    Do you have a system load?

    Thanks,
    John
  • Dear John.

    I want to confirm, you are charging at 2A?
    --> It is almost 2A

    Is the input power the same for both tests?
    --> Yes.

    Do you have a system load?
    --> No.
    This test is a symptom of only connecting the battery.

    Thanks.
  • Hi Chun,

    Sorry for my delay. The Current meter's internal resistance may be affecting the results. depending on how it is put into the system, the BAT pin voltage could be different and the charging current would be different. Are you measuring charging current and BAT pin voltage at the same time? Also, for measuring current we measure using a shunt resistor with multimeter.

    Thanks,
    John