BQ76972: Can't see BQ76972 in BatteryManagementStudio

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Can't connect to BQ76972 by using EV2400 at BatteryManagementStudio-1.3.124_Build1 , Already plug in 4S2P LiFepo4 to board and try provide 5V to TS2 and provide a 13.5V the pack+ but the BatteryManagementStudio still didn't see the device and the REG1 are no voltage output.(But the CP1 had 24V and BAT had 12V,LD and PACK pind also had about 12V,any one can help.

Hello Minki,

You can use the BQ76952 to connect with bqStudio.

To wake the device you have to pull-down TS2, not apply a voltage to it.

Does REG18 measure any voltage? This should be ~1.8-V if the device is ON.

Best Regards,

Luis Hernandez Salomon

Hi Luis:

Just can connect in bqStudio.

But i find few problem.

First is the TS3 keep in -253oC and i sure using the right B(25℃/85℃) 3435K NTC(TDK-NTCG103JF103FT1),

and i try to cal it the studio said out of range, how should i start the debug?Is that case by a parallel 10nF CAP?

And i can't charge or de-charge the pack even charge in 1A and de-charge in 4A,can help for check is the data had any problem?

Thank You1BQ79672.gg.csv

Hello Minki,

You must enable the thermistors in the registers. TS3 is disabled in your settings.

FET_EN is also disabled, this means that the DSG/CHG FETs would not turn on. The following application note may be useful: 

Best Regards,

Luis Hernandez Salomon

Dear Luis ,

Thank for the app note but after setting the TS3 to cell temperature and FET_EN still not working

And i found the the CP1 only about 15V now

Please help for checking again the setting

Many Thank 's

Test2.gg.csv

Hello Minki,

Looking at the image you shared, it looks like the part is working correctly. TS3 is measuring ~26degC and FET_EN is enabled, which shows that the DSG and CHG FETs are ON.

The battery voltage seems to be ~12-V, so I'd expect CP1 to be ~11-V above that, so roughly 23-V or so. Is that not the case?

Do you have a schematic for your design?

Best Regards,

Luis Hernandez Salomon

Dear Luis,

After power on/off cycle the  CP1 had 23.4V when battery at 12.75V,but even the FET_EN is enabled and DSG and CHG FETs are ON show in the studio,the gate of the CHG is just 12.69V and the DSG is 9.3V.

Still can't chage and decharge even i close all protection.

And i want to know the unit of USER A?

It should be direct enter the current sense resistor value in studio or according the formulae in APP NOTE?

For example i want the OCD3 cut at 700A after 35second....is setting like that? The unit should be -700,-7000 or -70000?

Please see the schematic.....but seem send to you before...

Many thank for help....please help me fix it

G24BMS_V05 cleared.pdf

Hello Minki,

You need to update your EV2400 to v0.32. Have you used an EVM to get familiar with how it works?

Minki Li said:

the gate of the CHG is just 12.69V and the DSG is 9.3V.

Still can't chage and decharge even i close all protection.

This sounds to me like the FETs should be ON here. Your MOSFETs have a turn-on voltage much lower than that. So, why can't you discharge/charge? Can you explain what you are trying to do? And your steps in doing so?

Minki Li said:

And i want to know the unit of USER A?

By default it is in mA. I would recommend you read Section 4.3 Coulomb Counter and Digital Filters of the Technical Reference Manual.

Minki Li said:

It should be direct enter the current sense resistor value in studio or according the formulae in APP NOTE?

When using bqStudio, you would enter your sense resistor value in mOhms. bqStudio will automatically convert this to values that the BQ769x2 can understand. So if you have a 1-mOhm sense resistor, you would input 1 in bqStudio.

Minki Li said:

For example i want the OCD3 cut at 700A after 35second....is setting like that? The unit should be -700,-7000 or -70000?

The setting of your OCD3 would depend on your userA. If your userA units are 100-mA, then you would make this -7000. Delay can be put in seconds, so 35-seconds would be okay. 

Minki Li said:

Please see the schematic.....but seem send to you before...

I think I remember!

One comment is that C8 should connect to Vss (not to VC0).

Best Regards,

Luis Hernandez Salomon

Dear Lusi:

>You need to update your EV2400 to v0.32.

Done

>Have you used an EVM to get familiar with how it works?

I didn't had the EVM.....

>This sounds to me like the FETs should be ON here. 

Yes it should but didn't on

>And your steps in doing so?

Case 1:

Connect the battery pack,only program Vcell mode to 0x8007,TS1 to 0x00,TS3 to 0x07,protect config to 0x2FET option to 0x1D

and CC Gain to 0.145.The CP1 will have 23V, but after send out the FET-ENABLE command the the CP1 will drop to 15.1V

Case 2:

Connect the battery pack,only config CC Gain to 0.145,TS1 to 0x00,TS3 to 0x07,Protection config to 0x00,FET option to 0x1d.Mfg state init to 0x50,After config those the CP1 only had 15.1V(Checked Chg pump control is 0x01)

Case 3:

1.Connect the battery,open studio

2.Measure CP1 23.4V,CHG12,722V,DSG 9.5V

3.Config Vcell mode to to 0x8007,CP1,CHG and DSG same voltage

4.Config TS1 to 0x00,TS3 to 0x07,CP1,CHG and DSG same voltage

5.Config Protection Configuration to 0x00,CHG and DSG same voltage

6.Config FET option to 0X1D,CHG and DSG same voltage

7.Config Mfg state init to 0x50,After config those the CP1 only had 15.1V(Checked Chg pump control is 0x01)

8.Config Mfg state init to 0x00,After config those the CP1 back to 23.4V,

9.Config Mfg state init to 0x40,CP1 keep 23.4V,

10.Config Mfg state init to 0x10,CP1 drop to 15.2V

It seem case by some config error?Some error bit i didn't clear?Of the circuit MOSFET config problem?

Should i remove the D6,Q7,Q16 D8,Q23,D7,D9 to test?

>One comment is that C8 should connect to Vss (not to VC0).

Yes i forget that but it should not be the course of that?

Other addition test,Config Mfg state init to 0x10,CP1 drop to 15.2V,CHG had 13.892V and DSG had 13.038V

Turn on the ELOAD at 10mA,CHG will drop to 12.1V and DSG will drop to 8.791V,V pack drop near zero,

Stop the ELOAD,CHG had back to 13.82V and DSG had 13.038V.

So .... it is the MOSFET control HW problem?

Many thank

Dear Lusi:

And do you know what happen on this error?