BQ40Z60: not charging

Marek Rist

Prodigy 170 points

Part Number: BQ40Z60
Other Parts Discussed in Thread: BQSTUDIO

Hi!

I have made a custom board with BQ40Z60 and I am using 4 cell configuration.

I connected this board to EVM2300 and am able to communicate with bqStudio.

I am unable to get the solution to start charging the cells.

I have played around with Fet_enable and charge_enable and most other commands.

I added an image of the registers and srec file (which the webpage wanted to display as video, therefore the long link)

Please could anyone with experience take a look at them and see if there is anything suspicious.

With best regards,

Marek

/cfs-file/__key/communityserver-discussions-components-files/196/3252.3362.test.zip

over 8 years ago

0 jury noname over 8 years ago

Intellectual 765 points

Hi!
I see FUSE=1 - are you really have fuse module or not?
if fuse is real - try to measure voltage after and until fuse. may be fuse is dead..
if fuse not - look in e2e.ti.com/.../battery_management - how block this alert..

0 ThomasCosby over 8 years ago in reply to jury noname

TI__Guru 73830 points

Marek
If the fuse feature is not used, then the AFEFUSE pin needs to be connected to VSS to prevent the FUSE flag from setting.
Tom

0 Marek Rist over 8 years ago in reply to ThomasCosby

Prodigy 170 points

Thank you jury and Thomas!

I connected the fuse pin to VSS and the FUSE flag disappeared.

Unfortunately It still wont start charging.

Now I see CF flag, asking for a conditioning cycle

TD flag, meaning terminate discharge alarm.

How this conditioning cycle could be performed?

Regards,

Marek

0 ThomasCosby over 8 years ago in reply to Marek Rist

TI__Guru 73830 points

The Conditioning Flag would not prevent the device from charging. You do have an ACLW lfag set, indicating that the adapter voltage is too low. What is the gauge reporting as the adapter voltage? Maybe it needs to be calibrated.

0 Marek Rist over 8 years ago in reply to ThomasCosby

Prodigy 170 points

The adapter voltage is 20V and the device reports it correctly 20069mV.
I have not found a field where to specify the lower limit for adapter voltage.

0 ThomasCosby over 8 years ago in reply to Marek Rist

TI__Guru 73830 points

There is not a protection feature for the lower limit. The ACLW flag will set, if the adapter voltage is too low.

0 Marek Rist over 8 years ago in reply to ThomasCosby

Prodigy 170 points

I have 4 cell configuration and I have tried increasing charger voltage up to 24V.

I have 25V capacitors so I dont want to experiment with higher voltages.

If the voltage of the fully charged pack is 16.8V, then how high must be the adapter voltage?

0 jury noname over 8 years ago in reply to Marek Rist

Intellectual 765 points

Hi!
for 3S configuration we use 19V wall adapter..
about "wont start charging" - check input circuit.. for example, if you schematic based of typical from bq40z60 pdf (page 30) - apply input voltage and make measure of voltage after 2n7002 and input FET, and pin 22

0 Marek Rist over 8 years ago in reply to jury noname

Prodigy 170 points

Hi!
With 24V adapter voltage the voltage at pin 24 is 22.8V
The voltage at the ACFET pin is 13V.

0 ThomasCosby over 8 years ago in reply to Marek Rist

TI__Guru 73830 points

Marek,
You must mean that the voltage at pin 31 is 22.8V. Pin 24 is power ground. I tested the test.srec file that you sent earlier and charging works properly on the EVM. Could you attach the schematic for your custom board? I can review it for errors.
Tom

0 Marek Rist over 8 years ago in reply to ThomasCosby

Prodigy 170 points

Hi!

Sorry, 24 was a mistake, probably since I had 24V adapter voltage in mind.

The pin was 22 as jury suggested to be measured.

I attached the schematic.

Regards,

Marek

0 ThomasCosby over 8 years ago in reply to Marek Rist

TI__Guru 73830 points

Marek,

The only issues that I see with the schematic are:

There needs to be a 10k series resistor from the adapter to the ACP pin. A direct short can damage the pin.
M1 is installed backwards. There was an error in the block diagrams in the datasheet, but they have been corrected. You could try just shorting across the ACFET for now. The ACFET is there to prevent current flow back to the AC Adapter.
C14 should be 0.1uF.

Tom

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BQ40Z60: not charging