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BQ24250 Evaluation module

Other Parts Discussed in Thread: TEST, BQ24250EVM-150

While following the recommended test procedure in the user guide of the BQ2425Xevm-150. I want to set up the battery emulator as mentioned in the figure 3 of user guide and I couldn't understand why you have TBH25P5R6 resistor pins 1 and 2 connected to ground? Why are you using 5.6Ohm resistor? Can you please explain the battery emulator.  Thanks.

  • I have test setup  that is mentioned in the section 5 of user guide of BQ2425xevm-150 with the battery emulator (figure 3) without the TBH25P5R6 resistors. 

    In section 5.5.1 when I measure A2 it is 670mA and A1 is 410mA whereas it is mentioned that the measure on A #2 is ICHRG = 1000 mA ±150 mA and Measure on A #1 is IIN = 600 mA ±100 mA. 

    In section 5.5.2 step 3 when I measure A2 it is 590mA and A1 is 40mA whereas it is mentioned that the measure on A #2 is ICHRG = 120 mA ±20 mA and Measure on A #1 is IIN = 100 mA ±20 mA.

    All the other measurements are also not matching the values that are mentioned in the user guide. Can anyone please let me know the reason for this difference in measurements? Thank you.

  • Hi,

     

    Make sure to use the right battery emulator and real battery for this test. Please understand that vin is 5V and the battery voltage is less than 4.2V at most.  

     

    Thanks

    Tahar

  • Thanks for the reply Tahar,  I am using the battery emulator circuit that is mentioned in the user guide. Can you please explain me the battery emulator and why do you have the 5.6ohm (TBH25P5R6) pin 1 and 2 connected in the circuit?

    Do this battery emulator circuit give the same measurements mentioned in the user guide? Thank you.

  • Hi,

    It is a 2.2-ohm high power resistor with head sink. It can sinks up to 4A/4.4V. On side is connected to BAT (As battery terminals) and the other to another power supply. The diode is used to protect the power supply from reverse current from the charger. This circuit is used as a battery emulator where the battery voltage can be adjusted by the power supply.  

    Thanks!

    Tahar

  • Thanks Tahar, Can you please let me know why do you have TBH25P5R6 in the circuit with pins 1 and 2 connected to GND? I have used the battery emulator circuit but the test measurements are not same as mentioned in the user guide. Do this battery emulator circuit give the same measurements mentioned in the user guide? Thank you.

  • Hi,

     

    That is the heat sink and the resistors needs to be connected to GND and +of power supply

     

    Please use a real battery or source meter such 2420 keithley and see if that helps.

     

    Thanks

    Tahar

  • Hi Tahar,

    I am not sure which real battery to buy for the test. Is it 3.6V or 3.8V or 3.2V battery? because under 5.5.1 section 3.2V battery is used and in 5.5.2 section first it is mentioned to follow section 6 where 3.8V battery is used and then 3.6V VBAT.

    I already have 3.7V battery but the test results are not matching to the user guide.

    Can you please suggest me which battery to buy in order to test the BQ24250EVM-150 board?

    Thank you.

  • Hi Tahar,

    I have used the real Li-Ion battery and implemented the 5.5.2 section by pressed the READ button in the bq2425x software and changed the input current limit to 100mA

    Measure on V#3 is VBAT = 3.8V

    Measure on V#2 is VSYS = 3.82V

    Measure on A#2 is Ichrg = 560mA

    Measure on A#1 is Iin = 390mA

    Changed the charge current to1000mA, input current limit to 900mA and battery regulation voltage to 4.2V in the software. But the measure on A#1 and A#2 are remaining the same as above. Can you please help me with it?

    Thank you.

     

  • I have notice that BQ2425x evaluation software is not working. Because when I change the CE pin to high on board and I see that there is no change in the CE pin status in GUI window or if I disconnect the battery there is no change to the fault status it is still normal.

    Please let me know how to make the BQ2425x evaluation software work. Thank you.