I have designed a bms with A cell balancer Bq77910a and a Bq34z100. The bq77910 works en communicates perfect.
a The Bq34z100 does not communicates at all. Only the two first two led's are lit up a very little bit . In the program i am receive a no acknowledge message .
So. there is something wrong whit the communication ., or maybe a supply problem ?
In the user guide there are many schematics which all uses a zener diode in series with a resistor . the connection between zener diode and resistor is connected to a 2n2007 Mosfet which is use to supply power to the chip.
In the remark of the schematic is suggested that you have to alter this series resistor to adjust the current to the chip.
In the Evm schematic in the user-guide the chip supply has to 2n200t Mosfet in parallel whit the serie resistor split up in two resistor. This is suggesting that more current is needed.
In all other sample schematics there is only one 2n7002 mosfet with a zener and series resistor.
Can some one tell me how i can dimension the chips power supply in a way the chip can works at its specs.
I have used a zener with the standard resistor . But the 2.5 Volts from the LDO is not stable and it goes up and down from 2.31. to 2.52. Volts
I will use 8 cells Lithium Fer cells.
Anyone that has suggestions to get this working please respond to this questions.
Many thanks in advantage for your reaction.