BQ34Z100-R2: VEN pin and BAT pin

Hello Nishie,

1- There's is no documentation about the exact timing of the BAT terminal and VEN but there is a 1 second interval when the battery gauge reads voltage

2- Not necessarily since the battery gauge is powered from the cell, also a most cells should never reach 0V since it would most likely cause irreversible damage

3- It should be 1 second but can also be dependent on the data flash parameter you've set your system too

4-I've marked up your schematic, the biggest concerns is orange however a lot of the reasoning for this is due to not seeing our application similar beforehand. Typically we recommend to stick with the evm/typical application schematic.

Thank you,
Alan 

Hi Alan-san,

Thank you for your support.

2. I apologize for my insufficient explanation. I think that when the FET in the red frame is Off, no voltage is applied to the BAT terminal. Is it OK if no voltage is applied to the BAT terminal regardless of whether the VEN terminal is High or Low?

4. Thank you for your check.

Would the following be okay as a fix?

- Change R1100 from 100kohm to 1kohm

- Remove R1087 and R1101

Best Regards,

Nishie

Hi Alan-san,

Even if VEN becomes GND level, will it be okay to make the specified circuit changes?

Best Regards,

Nishie

Hello Yuta,

I am currently looking into it.

Thank you,
Alan

Hi Alan-san,

I have some additional questions regarding the answers you gave me in the past.

Alan Frias said:

1- There's is no documentation about the exact timing of the BAT terminal and VEN but there is a 1 second interval when the battery gauge reads voltage

->You said that there is a 1 second interval when the battery gauge reads voltage, but is it correct to understand that it reads the voltage at the timing shown in the red box in the waveform below?

Alan Frias said:

3- It should be 1 second but can also be dependent on the data flash parameter you've set your system too

->Which data flash parameter can be changed to change the period of the voltage output from the VEN terminal?

Alan Frias said:

I am currently looking into it.

->I would like you to continue checking the circuit diagram.

Best Regards,

Nishie

Hello Yuta,

This pin is controlled internally by the IC's and lowers the current consumption.

Thank you,
Alan

Hello Yuta,

Yuta Nishie said:

->You said that there is a 1 second interval when the battery gauge reads voltage, but is it correct to understand that it reads the voltage at the timing shown in the red box in the waveform below?

-This is a design question and I would need to reach out for a response and response time can vary.

Yuta Nishie said:

->Which data flash parameter can be changed to change the period of the voltage output from the VEN terminal?

-I've attached a e2e for reference.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/856665/bq34z100-g1-how-to-control-the-output-of-the-ven-pin

Thank you,
Alan 

Hi Alan-san,

Alan Frias said:

This pin is controlled internally by the IC's and lowers the current consumption.

->Sorry. I'm confused because I sent multiple questions. Which question does this answer?

Alan Frias said:

This is a design question and I would need to reach out for a response and response time can vary.

Am I correct in understanding that you can have another team look into this? Thank you for your support.

Best Regards,

Nishie

Hello Yuta,

Yuta Nishie said:

->Which data flash parameter can be changed to change the period of the voltage output from the VEN terminal?

Yuta Nishie said:

->Sorry. I'm confused because I sent multiple questions. Which question does this answer?

-VEN is a pin that can't be controlled by the user, sorry for the miscommunication since I did state it was but that was an error on my end

Yuta Nishie said:

Am I correct in understanding that you can have another team look into this? Thank you for your support.

-I would have to go run test for this on my end to verified this and you should expect a result from this by mid of next week. But it could be possible VEN polls at 1 second however after consulting with the team voltage measurement are polled multiple times a seconds however it is only update once a second.

Thank you,
Alan

Hi Alan-san,

Alan Frias said:

-VEN is a pin that can't be controlled by the user, sorry for the miscommunication since I did state it was but that was an error on my end

->Thank you for notifying me of the correction. I understood that the output period of the VEN pin cannot be changed by the user.

According to the information confirmed by the customer, the output period of the EVM's VEN pin is 20 seconds, but is it correct to understand that this means that a register that cannot be changed by the user has been changed?

Alan Frias said:

-I would have to go run test for this on my end to verified this and you should expect a result from this by mid of next week. But it could be possible VEN polls at 1 second however after consulting with the team voltage measurement are polled multiple times a seconds however it is only update once a second.

->It would be very helpful for me to have you test it.

Is the measurement of the voltage input to the BAT pin also correct at 1 second? Also, is the trigger for the BAT pin to start measurement generated by a timer inside the IC? Or does the IC pin issue the trigger?

Best Regards,

Nishie

Hi Alan-san,

Do you have any update?

Best Regards,

Nishie

Hello Yuta,

Yuta Nishie said:

understand that this means that a register that cannot be changed by the user has been changed

-Yes this is correct

Yuta Nishie said:

->It would be very helpful for me to have you test it.

-Currently due to the workload this task has been pushed forward

Thank you,
Alan

Hi Alan-san,

Thank you for your support.

Alan Frias said:

-Currently due to the workload this task has been pushed forward

->Thank you for taking the time to respond. Is this test likely to answer my question about BAT pins?

Best Regards,

Nishie

Hi Alan-san,

I'm sorry to keep repeating.

Alan Frias said:

Please reference the e2e below where it stats "(VEN)It will pulse to 2.5V every 1 second when the voltage measurements are taken".

->Since it says "when the voltage measurements are taken," is it correct to understand that the measurement of the BAT terminal is performed every 1s?

Also, is it correct to understand that the measurement of the BAT terminal starts immediately after the IC starts and the battery is connected?

Best Regards,

Nishie

Hi Alan-san,

Thank you for your support.

1. I understand that the BAT terminal measures the battery voltage every 1s. Is it possible for the user to change the interval of this measurement?

2. 

Alan Frias said:

I've marked up your schematic, the biggest concerns is orange however a lot of the reasoning for this is due to not seeing our application similar beforehand. Typically we recommend to stick with the evm/typical application schematic.

->Is it correct to understand that the reason for changing the value of R1100 from 100k to 1k is to increase the current flowing to the FET? Also, could you tell me the problem with using R1100 at 100kΩ?

3.

Alan Frias said:

BAT pin does pulse every 1 second when the voltage sensing takes place

->Is the timing of the BAT pin's one-second pulse generation counted by the IC's internal timer?

4. When the VEN pin is connected to the GND, how does the timing change when the BAT pin starts measuring? Does it remain one-second?

Best Regards,

Nishie

Hi Alan-san,

Thank you for checking. Please let me know if there is an update.

Best Regards,

Nishie