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BQ2954 power management IC

Ashik Das
Prodigy 10 points
Other Parts Discussed in Thread: BQ2954

  • Hello Sir/Madam,

                                        I have question regarding your product BQ2954 power management IC. This following IC i am using for my University senior project to charge a 1-cell 3.7v Lithium-Ion battery. I used a circuit that is given on the data sheet (http://www.ti.com/lit/ds/symlink/bq2954.pdf). Also, i am using some of the replace parts according to it's similar specification. The replacement part i selected are:

      FMMT3906 with 2n3906

    FMMt304 with 2n3904

    FMMT451 with TIP29

    FMMT3904 with  2n3904

    FZT789A  with TIP32AG

    I followed the exact circuit as shown in the data sheet (figure 3), however when i connect the rechargeable battery to out put battery terminal it shows the increase of current in power supply but at pin 2( CHG) there is no voltage and at pin3 BAT show low (0v). Also, the LED at pin 15 LED/CSEL show HIGH but at absence of battery it remain HIGH until i turn of the power supply. Please help me because i need to complete my senior project by MAY 7th. 

    Also,

  • 1) We are connecting 1 cells in series, total battery pack voltage for the 1 cells is arnd 3.7V (arnd 3.3V per cell).

    3) The reason we can't use a new IC as you suggested is because, this is our Final Year Project, and it ends this month by the end of may 7th. Thus we do not have enough time on our hand to implement a new circuit. So, since we have been researching and working on this bq2954 IC, we have almost got everything correct except this charging current. Thus,we hope to identify and rectify the problem with this IC itself, given the lack of time.

    Some more info on our circuit when its charging the cells:

    • Our bq2954 charger circuit is working on mode 3 (as set by the DSEL pin)
    • When our battery is connected and the circuit is switched on the following is our LED statuses:

    LED 1: ON

    LED 2: OFF

    CHG pin LED: OFF

    BTST pin LED: ON

    • And when our switched on but the battery is not connected, the following is our LED statuses:

    LED 1: ON

    LED 2: OFF

    CHG pin LED: ON

    BTST pin LED: ON

    Thank you