BQ4050: unexpected operation

Bq4050evm-561

After we replaced the load resistors to 5 ohm (~2A LOAD), we calibrated the current , voltage and temperature.

After programming the bq4050evm-561 with your srec file we get the next state:

Pack voltage is 10 Volt, charging with pre-charge fets.

We used the default data memory file.

at charging configuration with 300 ohm resistors for each battery cell( without battery) we get the next state:

Fets remain not conductiong even though GUI shows XDSG & XCHG are set so 0.

if we disable the "fet_en" , the same happens : XCHG fet is not conducting in contradiction to it's flag

We used the default data memory file.

In our setup we used EV2400 HPA500 and EV2300 . both devices results the same.

If we look at the read registers at the GUI we see the next important beahvior

• Operation status[SDV] is '1'.  The Exit condition exists(10 volts at pack pin) , but [SDV] is still on.
• Additionally ,operation status [FUSE] is '1' ((the gate resistor of the fuse blow fet was soldered out to prevent the fuse blow))           

 in addition , i attach some measurements which maybe help you to find the solution :

Charge fet gate voltage –switching period 1 sec

zoom at the charge gate voltage

DisCharge fet gate voltage –switching period 1 sec

Zoom at the discharge fet voltage

It looks like the gas gauge tries to switch the fets to on stats but something prevents it or doing so.

The fuse pin switches at 166mHz with 50% duty cycle

Then we connected the setup in Discharge configuration

Fets are still not conducting although GUI shows XCHG and XDSG are '0'

Charge fet voltage

DISCharge fet voltage

Fuse pin is constant 1.1 volts

i hope you will be able to find a solution . 

Best,
victor