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how are u doing
i want to use the amc1301 to sense a power ac line that has an amplitude ranges from 0 to 700 volts with frequency of 60 hz
as i see i need to use resistor divider network at the input of the AMC1301 so when the ac line is 700v the max amplitude at VINP pin is 250mV .(i connect the VINN to ground )
but i have a problem with this design and my problem is when the power line amplitude reduces down to 100 volts or less i get very low input voltage at VINP about 5mV and its not very big swing at the input of the isolation amplifier .
do have any recommendation of how to sense high ac voltage like in my case
i can solve this issue by connecting a different resistor network so when the amplitude voltage gets down to 100volts i start to use another resistor divider network that give me 250mV at the input of the amc1301
but i want to see if you have another approach for sensing an voltage with an amplitude of 700 AC volts using the amc1301
Alex SmithApplications Engineer | Precision Delta-Sigma Converters
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In reply to Alexander Smith:
yes you are right 100v is equal to 35mv
the resistor network is 10K and 3.5ohm
do you have a recommendation for other resistors values?
and yes i intend to change the resistor network by hardware but i wanted to see if there is another idea for doing this measurement?
In reply to AIED BEBAR:
thanks for your help
i did a simulation using TINA for the reinforced amc1301 circuit that is in tidubx1b.pdf
for sensing the DC bus input voltage.
i wanted to sense a 566 AC volts with 50 hz frequency
and i got the following results
the peak value of the input signal is 322mv
and the minimum value is -124mv
and the output of the opamp was clamped at the maximum and not a full sin wave
i expected to see +/- 250mv at the input and a full sine wave at the output i tried of biasing the input but the output was still clamped ,do you have any idea why? how to correct the circuit in order to utilize the range of the 250mv input 566volt main line sense1.TSC
i attached the Tina design
hii alex ,how are you doing
did you see my question?
hope you had a good refreshing holiday :)
i attached a screen shot of the simulation
as you can see the input is with 322mv max amplitude and -124mv when i take the deference between this values its about 340mv which is much higher than 250mv input swing of the device this is one problem
and the second one is this input sine wave is not centered around 0v
from the resistor divider network at the input should be 250mv once there is 566v at the input line .
and the out put op the opamp is clipped at the max peak of the output wave , and yes the output should be between 0 and 3v cause i feed it to my ADC e output of the opamp should be between 0 to 3v cause i feed to my adc
hii i also attached the schematic that shows the resistor network that i use at the input
by voltage division if there is 566 VAC by phase i should sense 250mv
and this is not happening in the simulation the amplitude as i mentioned above 322mv and -124mv
and i suspect that is whats causing the clipping at the output on the op amp.
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