BQ2000: Current sense resistor

Vsevolod Elantsev4

Intellectual 2810 points

Other Parts Discussed in Thread: BQ2000EVM, BQ2000

Hi team,

My customer changed current sense resistor R3 in BQ2000EVM to 0.1 Ohm and expected to have 0.5A chare current.

According to a datasheet Eq. 4 current should be 0.05 / 0.1 = 0.5 A.

But really they have around 300mA charge current.

What can be reason of such low current?

over 6 years ago

0 iAlejandro over 6 years ago

TI__Expert 8130 points

Hi Vsevolod,

What type of cell chemistry is being used with the charger?
We will try an replicate this issue. According to the datasheet (like you stated) it should be providing 500mA of fast-charge current.

Regards,
Alejandro

0 iAlejandro over 6 years ago in reply to iAlejandro

TI__Expert 8130 points

Vsevolod,

We haven't heard back from you. We are assuming you were able to resolve your issue. If not, just post a reply below or create a new thread if the thread has locked due to time-out.

Regards,
Alejandro

0 Vsevolod Elantsev4 over 6 years ago in reply to iAlejandro

TI__Intellectual 2810 points

Alejandro, sorry for the late reply.

The customer use a Li battery.

0 Fai Leung over 6 years ago

Prodigy 135 points

Hi Vsevolod,

I am using BQ2000 in my project to get 1A charge current and I also got the same issue in my first version PCB. Issue happend because the trace which in-series to the circuit is also apart of shunt resistor. You have to increase the width and decrease the length of the trace. I also suggest you to put few pieces same value resistors in parallel to get the value you need. Then, you can fine tune their quantity to get actual current afterwards.

Here shows apart of my PCB with the shunt resistor.

Best regards,

Fai.

0 ezhao over 6 years ago in reply to Fai Leung

TI__Genius 10240 points

Hi Fai,

Thanks for sharing your experience.

Hi Vsevolod,

Hope Fai's comment helps solve your issue.

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BQ2000: Current sense resistor