• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 268 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ77PL900 5 - Cells

Paolo Lisanti
Prodigy 10 points
Other Parts Discussed in Thread: BQ77PL900

Hi, 

I've a problem with five cells connection with IC BQ77PL900.

I've read information reported in its tecnical Documents and I've done:

- Set Configuration bits (CNF2 = Vreg2 , CNF1 = 0, CNF0 = Vreg2) to Vreg2 (3.3v) by a 100k resistor, or to GND. Is it normal that i read 2.6v at CNF2 and CNF0 pin?

- Shorted unused Vcell pins (from Vc1 to Vc7).

After pack connection, CHG and DSG MOS are both off. Even If I attach a charger, CHG and DSG MOS  remain in off state.

Voltage at PACK pin and BATT pin are in normal condition.

Thanks, 

Paolo

 

  • 0
    TI__Guru 54715 points

    2.6V is low for a 100k pull up to 3.3V on the CNF pins. If Idown was maximum you would expect ~0.4V drop on the 100k resistor.

    You do not mention VLOG in the connections.  It should be connected to VREG2 (3.3V) from the description. If that connection is not present or has high resistance, the part may be trying to power up through the CNF pins thus resulting in a high current into and low voltage on the CNF pins, and failure to operate due to insufficient voltage at VLOG.

    If VLOG is correct, other things to check are that the cell voltages are correct at the VCx pins and within the normal limits of the EEPROM settings. If all inputs are correct, the part may be damaged.