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# tlv9062 with 5mOhms resistor

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#### v1.5

##### Member
Hello there.
I plan to measure current from low side with resistance and I don't know if some of the components I have are ideal for this job. there is a 5mOhms shunt resistor , The datasheet of the shunt resistance is shared below. this is the tlv9062 opamp 's datasheet and that i will use to measure the low side current.
I have to talk about the system first. The system will measure the current of the low side igbt of an alternating current motor that will draw a maximum of 5 amps of current. There is a circuit diagram in the datasheet of Tlv9062 opamp (Figure 38) and in this scheme the voltage drop of 100mV is increased to 4.95V with the non-inverting amplifier. As you know, the shunt resistance in my system is 5mOhms (+ - 5%). this makes a 25mV voltage drop for 5 amps and this is valid at maximum condition. In fact, the motor cannot be expected to draw more than 5 amps in normal operating condition. I want to measure relatively low currents such as 1 ampere with this shunt resistor and I want to publish the measurement value with a user interface. Do you think a shunt resistor of 5mOhms with tlv9062 can measure a voltage such as 5mV? I am waiting for help because I cannot understand the part of this in datasheet. thank you.

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The circuit looks good. Rail to Rail in & out is key.

The input offset voltage may add some errors if you are going to have only 5mV across the shunt. Data sheet 8.10 The input of the amp will typically be + or -0.0003 volts off from what you think. Worse case is +/-0.0016V. So the 5mV might read 5.3mV or 4.7mV typical.

Gain is set at 5X so 5mV=25mV.

At motor start up the current will get above 5A but you might not care.

The circuit looks good. Rail to Rail in & out is key.

The input offset voltage may add some errors if you are going to have only 5mV across the shunt. Data sheet 8.10 The input of the amp will typically be + or -0.0003 volts off from what you think. Worse case is +/-0.0016V. So the 5mV might read 5.3mV or 4.7mV typical.

Gain is set at 5X so 5mV=25mV.

At motor start up the current will get above 5A but you might not care.
View attachment 126711
Thank you so much. I ll try it this weekend.

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