Part Number: INA214
When the customer using INA214 to sense the input current at the input, they find that the same value of input current(different input voltage), OPA amplified value (pin6) is different.For example, Rsense = 2 mohm, input voltage 40~72V, adjust the load so that the input current is about the same 5.7A40V, 5.7A → 594 mV48V, 5.7A → 616 mV60V, 5.7A → 630 mV72V, 5.7A → 652 mVIt is suspected that the input current is too dirty, causing the amplified voltage error.
Subsequent adjustments the R14 & R15 resistance value from 2 ohms to 1 kohm or so, they found that the above problems can be improved (filter more strong);But the whole gain drops from 100 to around 50, I think it should be related to gain error factor.
1. What is the side effect if we change R14 R15 so large, will there be other effects excepts smaller Gain's & slower response?
2.Why datasheet suggest "External Series Resistance" should smaller than 10 ohm?
3.what will you suggest to solve this issue? Change which components or change to which devices?
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In reply to kai klaas69:
Ok, I will keep the R14 & R15 as 2ohm.
The 2mR is sitting at GND (low side). I really use DVM to measure the shunt R cross voltage to make sure "adjust the load so that the input current is about the same 5.7A", so I think there is no problem at precision.
R16 10kohm is use to adjust output voltage for MCU ADC, shown as illustration. Does here has any problem ?Actually, I find the solution to solve this issue.
I adjust the C9 & C10 from 6800pF to 0.22uF, there has great improvement on this issue.
In reply to Edward.Zhang:
Thanks for the help, we can close this thread!
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