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Original question:

BQ76952: Unable to connect BQ76952 with PC

BQ76952: BQ76952

Prasad Murugan
Prodigy 50 points
Part Number: BQ76952

HI Team,

In the datasheet on page number 193 and figure no 20 you have provided as a typical application with a processor controlling the BQ76952.

Suppose I use the same design, but without a controller in standalone mode. The TS2 pin responsible for waking up is used in a similar way as in figure no 20 for measuring temperature.

For the purpose for waking up the device I will have to use LD pin. In section 6.3 "Recommended Operating Conditions", it is suggested to use 0.95V to 4.5V on LD pin. In figure no 20 LD pin is connected to PACK+.

My first question is, if I connect a load to this PACK+ terminal instead of a charger how would you make sure that 4.5V is applied to LD pin so that the device wakes up.

My second question is Instead of connecting LD pin to PACK+ terminal can I connect it to BAT pin or on the high side of 16 series cells so that the device stays awake all the time.

Thank you,

Prasad M

  • 0
    TI__Guru 54715 points

    Hi Prasad,

    If you connect the part like figure 20 (using a complete schematic), TS2 is always held low and the part will stay awake.

    Q1: If a load is connected to PACK+ the part will not wake up (if TS2 is open).  A charger would have to be attached instead or in addition to the load to pull up PACK to wake the part.  PACK does not have to come very high as you noted.  If you have separate charger and load terminals PACK can connect to the charger, but wake is from the LD pin.  A wakeup solution is needed on the TS2 pin if the pack is to be shutdown.  See the application note https://www.ti.com/lit/pdf/slua952 

    Q2: LD should not generally be connected to BAT since it will affect fault recovery, however with host control it should be possible.

  • 0 in reply to WM5295
    Prodigy 50 points

    Thank you for the quick reply