INA286-Q1: Use INA286 to detect 0.1mv

liang ren

Intellectual 420 points

Part Number: INA286-Q1
Other Parts Discussed in Thread: INA286, TLV313,

I would like to detect 0.1mv--20mv of a 2mohm R(current is 0.05mA~10A)，

the INA286's output is 10mv--2v. The AMC1211's output is (1.44-1~1.44+1),

the TLV313's output is 1.5*(0~2)=0~3v , this will be transmit to mcu's 12 bit ADC(3.3v power).

I am not sure if it works ,or I should use a 10mohm R instead , then the detect current scope will redued to 0~2A

over 5 years ago

0 liang ren over 5 years ago

Intellectual 420 points

It should be 0.1mv--20mv of a 2mohm R(current is 0.05A~10A)

0 Patrick Simmons over 5 years ago in reply to liang ren

TI__Mastermind 23875 points

Hello Liang,

Thanks for considering to use Texas Instruments. The calculated outputs you have for each stage of your circuit look correct. However, the INA286-Q1 could present an undesired degree of error at 0.05A. This would be due to the offset voltage referred to the input. As your ideal expected minimum Vsense would be 100uV and the typical offset is +-20uV, you could have a 20% error or even as high as a 70% error from input offset alone. Do you absolutely need this resolution? If so, you could use a larger resistance as you suggested above. Perhaps you could use two shunts in parallel to get a 5mohm resistance. Are you expecting the common mode to your current shunt monitor to go well below 0V?

0 liang ren over 5 years ago in reply to Patrick Simmons

Intellectual 420 points

Hi Patrick

Yes, there is another circuit to detect current under a negetive common voltage of -12.6v, so I select INA286, the GND of 6 battary seris is on the middle position. If I use a low side current detect on the GND position, the current maybe bidirection

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INA286-Q1: Use INA286 to detect 0.1mv