BQ24770: About charge current measurement method using IBAT

Hi Yusuke,

I tested this on an EVM using the customer's register settings, but IBAT is working correctly for me. The IBAT pin voltage is about 207 mV, which is within spec.

The customer's register settings have IBAT enabled (ChargeOption1() bit[11] = 1) and set the IBAT output to monitor the charge current (ChargeOption2() bit[6] = 1), so I don't see any issues there.

When you say that IBAT does not detect the charge current, do you mean that the IBAT voltage is roughly zero? Can you please measure the actual charge current as well as the voltage drop across the sense resistor?

Best regards,

Angelo

Hello Angelo-san,

Thank you for your kind support.
〉When you say that IBAT does not detect the charge current, do you mean that the IBAT voltage is roughly zero?
Yes.
〉Can you please measure the actual charge current as well as the voltage drop across the sense resistor?
I will list the measured data of ”actual charge current” and ” voltage drop across the sense resistor” when IBAT cannot be measured.

Charge current,Vsrp-Vsrm,Ibat
0.0A,0.02mV,3.2mV
0.2A,2.05mV,3.3mV
0.4A,4.06mV,4.2mV
0.6A,8.03mV,3.5mV

By the way, when discharging, it is as follows.
Discharge current,Vsrn-Vsrp,Ibat
0.0A,0.01mV,02.3mV
0.2A,2.06mV,32.5mV
0.4A,4.07mV,64.3mV
0.6A,6.06mV,96.2mV

I will attach the material about the changes from EVM.
They have modified the following points from the schematic on page 13.
https://www.tij.co.jp/jp/lit/ug/sluuao3c/sluuao3c.pdf

bq24770 EVM changed parts list.pdf

Please advise any concerns as to why the charging current cannot be monitored using IBAT.

Best regards,
Yusuke

Hello Angelo-san,

Have there been any kind of developments concerning this matter?
Customers are wondering why they can not use IBAT to monitor charging current.
Please advise if you have any concerns or concerns to check.

Best regards,
Yusuke

Hi Yusuke-san,

Thanks for sending the data. It is definitely possible to use IBAT to monitor both the charge current and the discharge current.

I looked through the component changes in your PDF, and I don't think they would cause the IBAT pin to correctly monitor the discharge current, but not the charge current.

Can you please read back all of the registers and send them to me so I can make sure they are set correctly? The IBAT Output Select bit is especially important. If IBAT is set to monitor the discharge current when the battery is actually charging, then the IBAT voltage will be zero. This would explain the data that you collected.

At POR, IBAT Output Select = 0, which sets the IBAT pin to monitor the discharge current. I think the first thing to confirm is whether the IBAT Output Select bit was successfully changed to 1 when the customer wants to monitor the charge current instead of the discharge current.

Best regards,

Angelo

Hello Angelo,

Thank you for your response.
Customer register settings are as follows.

0x12H = 0x00CE
0x3BH = 0x6E01
0x38H = 0x4BD4
0x14H = 0x0400
0x15H = 0x2EE0
0x3EH = 0x2400
0x3FH = 0x0600
0x3CH = 0x4B74
0x3DH = 0x3109
0xFEH = 0x0040
0xFFH = 0x0114

Customer again tried to check ChargeOption2() bit[6] using Battery Management Studio.
However, the command of charge option 2 is 0x3C by mistake as follows in Battery Management Studio.
They suspected a display error, but couldn't monitor the charging current when changing this setting.
How do you check ADD:0x38H Charge Option 2 Bit[6] ?
They want to consider Advanced Comm I2C, but their evaluation environment is SMBus only.
Could you give me your advice?



Best regards,
Yusuke

Hi Angelo,

Thank you for your response and support.
I am glad that I could know GUI error this time.

My email address is ;
tsukui-y@macnica.co.jp

Best regards,
Yusuke

Hi Angelo,

Thank you for the email.
I confirmed the received file with Battery Management Studio.
I report this file to my customer.

Best regards,
Yusuke

Hi Angelo,

Thank you for your kind support.
Customer confirmed ”ChargeOption2() register” with the updated BQStudio GUI
And Customer set "ChargeOption2() bit[6] = 1" and measured IBAT again and it worked.

Best regards,
Yusuke

Hi Yusuke,

Thank you very much for reporting back! I'm glad the issue is resolved.

Best regards,

Angelo