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At present, I have a project to use ina148 chip again. During the use, the sampling output value drifts. The output value jitters about 0.2V. The attachment is the schematic diagram and ina148 output waveform for reference.
The general situation of the project is as follows:
1. Power supply voltage: DC regulated power supply, maximum output 60V / 30a, small power ripple, VPP < 3%
2. Basic introduction of the circuit: two resistors are connected in series in the power supply circuit (the resistance changes according to the field conditions, and the resistance range is 0.001 ohm - 15K Ohm). The power supply is provided to the two resistors through the power supply, which is basically the switching power supply directly supplies power to the two series resistors.
3. Two ina148 chips collect the voltage of the two resistors.
When the resistance voltage difference is less than 2.5V, direct sampling, the value is correct without jitter, if the voltage is higher than 2.5V, through 100k / 1K. Two resistance partial voltage sampling, at this time, the value has 0.2V jitter. In the software, the filtering algorithm order + median + average, each sampling 10 times for filtering.
Manager Zhang, please help me analyze if there is any problem with this circuit or have any good suggestions. Thank you.
