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INA180: Amplifiers forum

Gkarthik
Prodigy 100 points
Part Number: INA180
Other Parts Discussed in Thread: AMC1301, TMCS1100, TMCS1101

HI I am using INA180 in my circuit measure the Current  for the AC load ( Voltage 110V). The INA180 is supplied by 3.3V and the sense resistor value used is 1mohm . The max current will be around 10A .

Can I use INA180 , please provide your suggestions , I am new to this design

  • 0
    Guru 140200 points

    Hi Gkarthik,

    can you show a schematic?

    Kai

  • 0 in reply to kai klaas69
    Prodigy 100 points

    hi 

    Below is the Schematics. I am using a shunt resistor 1mohm . The current has to be measured on the AC line 230VAC, high side current monitoring is used . The accuracy required is 1% or 2% . The maximum current through the path will be 20A. I used the current sense amplifier INA180 but it has common mode voltage very less. Please let me know if this circuit works.

    Also suggest any suitable amplifiers for this application that can sense the current from 200mA to 20A . Since this is high voltage , do we need add any transient Protection. the Requirement  is to use only non isolated current measurement method. I am running out of time , your quick reply is much appreciated

  • 0 in reply to Gkarthik
    Guru 140200 points

    Hi Gkarthik,

    your schematic didn't come through. Please use the "Insert File" button (paper clip) in the header of input box.

    Kai

  • 0 in reply to Gkarthik
    TI__Mastermind 26660 points

    Hello Gkarthik,

    Unfortunately, the INA180 cannot be used in this application without added isolation or voltage-level shifting circuitry. This is because the common-mode rating of the INA180 is 28V to -0.3V, so nowhere close to 230 VAC. Most of the current sense amplifier cannot measure currents on AC voltage rails and still be powered with a single-ended supply voltage.

    The way to get around this create an AC-DC full-bridge rectifying shunt regulator that will generate a small supply voltage for INA180, but will also float with the input AC rail. Once this is done, then output voltage of INA180 will need to be measured with isolated ADC or digitized and then passed through an isolated I2C buffer.

    Another option could be using an isolated current sense amplifier like the AMC1301, but you will still need some full-wave rectifier shunt regulator to generate a supply voltage for the high-voltage side of the AMC1301.

    Hope this helps,

    Sincerely,

    Peter

  • 0 in reply to Peter Iliya
    TI__Genius 16080 points

    An alternative to measure directly on the AC mains is to use the TMCS1100 or TMCS1101 Hall Effect Current sensors.  They can be directly connected on the AC lines.  You mention the max current is 20A which is the max continuous current these devices can support.  So as laong as the average current is under 20A, you should have no issues.