BQ76952: REG1 VOLTAGE as Monitoring voltage

jian zhang

Part Number: BQ76952

MR,

For our product, we need to use BQ76952 reg1 voltage to check BQ76952 run normal or not.
First we set register 0x9236 with 0x0d and we hope reg1 product 3300mV.
We need to know if BQ76952 run abnormal reg1 will not product 3300mV.

For example ,if the voltage of reg1 is below 3100mV or is high than 3500, we will think the cell voltage and temperture read from bq76952 is not volid.

If this way is right , you give me some materials to confrim this way.

over 1 year ago

0 Andria McIntyre over 1 year ago

TI__Expert 8526 points

Hello,

Please see Section 7.12 in the BQ76952 Datasheet (BQ76952 3-Series to 16-Series High Accuracy Battery Monitor and Protector for Li-Ion, Li-Polymer, and LiFePO4 Battery Packs datasheet (Rev. B) (ti.com))

As you can see in the table above, when REG1 is set to 0x0D (3.3V output), the min votlage output on the REG1 pin will be 3V and the max will be 3.6V.

You are correct that the voltage supplied by the REG1 LDO will affect thermistor measurements, due to the properties of a voltage divider, where Vout = Vin(R2/(R1+R2)). If Vin is varied, Vout will be directly affected. This is why the REG1 LDO does not vary from 3.3V more than +/-0.3V

Best,

Andria

0 jian zhang over 1 year ago in reply to Andria McIntyre

Prodigy 170 points

Andria,

Thank you . Another issue, when REG1 voltage is below 3V or high than 3.6V, will REG18 voltage become abnormal ?

0 Andria McIntyre over 1 year ago in reply to jian zhang

TI__Expert 8526 points

Hi Jian,

If you notice that the REG1 voltage output is consistently outside the datasheet spec under recommended conditions, this could mean that the device is damaged. If this is the case, then the REG18 voltage could also vary. When a device is damaged, it can be hard to predict its behavior.

To ensure that the device is not becoming damaged, please see the Absolute Maximum Ratings table for abs min and max input and output that the REG1 pin can handle before being damaged.

Best,

Andria

0 jian zhang over 1 year ago in reply to Andria McIntyre

Prodigy 170 points

Andira,

=>This is good. Do you give me some material for me to write it to product test data

0 Andria McIntyre over 1 year ago in reply to jian zhang

TI__Expert 8526 points

Hi Jian,

For details on the voltages you can expect from the REG1, REG2, and REG18 pins, see the BQ76952 datasheet I linked above.

For more information on configuring registers, see the Technical Reference Manual linked here: BQ76952 Technical Reference Manual (Rev. B) (ti.com).

For more information on the BQ76952 software with example code, please see the Software Development Guide linked here: BQ769x2 Software Development Guide (Rev. B) (ti.com).

Best,

Andria

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BQ76952: REG1 VOLTAGE as Monitoring voltage