BQ40Z60: Configuration for Standalon

hi Felix,
Are you not trying to use the battery gauge functionality of the device as well. The bq40z60 is designed to be used as a gauge and charge in one solution. For further details, pls reference the technical reference manual of the device.

www.ti.com/.../sluua04

thanks
Onyx

hi Onyx,
thank you for your answer.
First I want to use only the charging-feature, after that I will try to get the gauge working.

I have read the manual but there are still some open questions.
After I have sent the CHAREGER_EN-command the device chip tries to enable the AC-FET in short impulses. But the CHG and DSG bits in the operation-status are not set, which means that the charging and the discharing FETs are not enabled. Also the XCHG and XDSG bits are set, I think they mean the same...?
What can I do so that the firmware enables the Charge- and Discharge-FETs?

Felix

Hi Felix,
You need to send the FET enable commands : mac access command (0x0022) to turn on the fet, afterwhich the device will automatically regulate them. Until you do so, they will remain off.

thanks
Onyx

Hi Onyx,

I found out that it is possible in manual FET-control (FET_EN = 0)  to charge the cells. Therefore I enabled the charger and turned on the CHG-FET. So the buck-converter is working with the right current (1 Ampere) and this is also displayed on the current-meter in the battery studio.

But as soon as I go to firmware-FET-control (FET_EN = 1) both the charge- and the discharge-FETs are turned off. Only the the step-down converter is working but no current can flow in the cells, as the FETs are off.

Do you have any Idea what is stopping the charge-FETs from turning on?

Thanks for your support,

Felix

Hi Felix,
I see in operation status your fuse is turned on. Send mac access command 0x001D to clear that fuse flag, then enable firmware control of the fuse by sending mac access command 0x0026, issue a reset command (0x41) then enable enable firmware control of the fet and let me know if that helps. If no, pls send a screen shot of bqstudio registers like you did before.
thanks
Onyx

Hi Onyx, thanks for your answer!

I solved the Problem with the fuse already by connecting a pulldown to the AFEFUSE-pin.

This is the new register-view, as you can see the FETs are still off:

Hi Felix,

The registers are always key to identifying where the problem is with the gauge. For future purposes when debugging this gauge if not behaving as should, the first thing to check would be the permanent failure registers, then the safety status register, then the manufacturing status register, then operation status register, then battery status register, then battery mode register. That is the process i followed in trying to figure out what is wrong with your device.

There are three flags set that might offer an indication of what is wrong.

First the TCA and TDA flags are set. If those are set,the firmware turns off the charge and discharge fets. Can you send the Reset command (0x41) to see if that clears them?

The other thing is the chgM flag is set meaning manual charge control by your host. This means your host controls the charging current and charging voltage. What do you have your charging currents and voltages set to in DF. Can you set the BCAST flag so the gauge controls the charging voltage and currents using the corresponding values in DF. Note that if any change is made to DF, you have to issue the reset command (0x41) so that parameter gets updated in RAM.

Most importantly, you need to have the PRES flag set. This means the gauge has detected that a battery is inserted. If a battery isn't inserted and the NR flag is clear, the PRES flag will be clear. pls see section 5.2.1 or the TRM. Also see EVM user guide. Short the Syspres pin to ground. That will set the PRES flag and turn clear the TCA and TDa flags and turn the fets on.

Let me know if this solves your problem
thanks
Onyx