BQ4050: Evaluate the theoretical current accuracy

zehu chi

Part Number: BQ4050

Tool/software:

Hi TI engineer:

How to evaluate the theoretical current accuracy and the fluctuation of current values for BQ4050?

If the sense resistor is 0.5 mΩ, what is the theoretical current accuracy of BQ4050, and what is the fluctuation range of the current value?

Thank you,

Zehu

over 1 year ago

0 Alan Frias over 1 year ago

TI__Guru 50130 points

Hello Zehu,

This question has been assigned and a response is being worked on.

Thank you,
Alan

0 Alan Frias over 1 year ago in reply to Alan Frias

TI__Guru 50130 points

Hello Zehu,

The biggest limitation for most current accuracy is typically software limited rather than hardware. The reason is due to the the algorithm rounding the current value either up or down depending on the case leading to a output of a whole decimal value. That being said we do recommend a 1mOhm sense resistor to be used and a lower resistor could work in higher discharge rates or be insufficient if the system is constantly discharging at low rates.

Thank you,
Alan

0 zehu chi over 1 year ago in reply to Alan Frias

Intellectual 735 points

Hello Alan，

In the current sampling section of other BQ chips, we found that there is a voltage value(9.35uV,As shown as below) corresponding to the LSB.

In this case, dividing this voltage value by the sense resistor value gives approximately the minimum current error value. For the BQ4050, is there a similar LSB voltage value?

Thank you,

Zehu

+1 Alan Frias over 1 year ago in reply to zehu chi

TI__Guru 50130 points

Hello Zehu,

In terms of LSB voltage value for BQ4050, please reference section 6.14 of the datasheet.

Datasheet:
https://www.ti.com/lit/ds/symlink/bq4050.pdf?ts=1752506073093&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FBQ4050

Thank you,
Alan

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BQ4050: Evaluate the theoretical current accuracy