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AMC1200: Front-end design of AMC1200.

seogje cho
Prodigy 110 points
Part Number: AMC1200
Other Parts Discussed in Thread: AMC3301

Tool/software:

Hello,
I am designing the Power Monitoring Device for AC220V. In the voltage measuring part,
I need isolation. So, I want to use AMC1200, a device for a fully Differential Isolation Amplifier.
But I am new to this IC, so I don't know if my design is correct.
The following is the schematic for the AMC1200 part.
I would appreciate it if you could tell me whether it is correct or not.


Thanks,

  • 0
    TI__Guru 51051 points

    Hi Seogje,

    In general this is correct, but it is important to note that all the high side VDD1 supply must be referenced to GND1 (GND2 net) which is in the mid point of the resistor divider. 

    Is this for a single or 3 phase voltage measurement? 

    To simplify the design, you could consider a device such as AMC3301 with integrated DC/DC converter. 

  • 0 in reply to Alexander Smith
    Prodigy 110 points

    Hi! Alexander,
    Thanks for your reply.
    My design is for the single-phase AC220V voltage measurement.
    I have changed the schematic as follows.

    I am attaching the power supply for the ACM1200.

    I have two concerns.
    One is that this schematic is immune to that if the user swaps between ACL and ACN Lines. The Other is that the output of AMC1200 is shifted above the zero point.

    Am I right?

  • +1 in reply to seogje cho
    TI__Guru 51051 points

    Hi Seogje,

    I see, I think your implementation is a clever way to handle swaps between ACL and ACN. This is OK for the AMC. I cannot comment for the U2. 

    The output will be shifted above the zero point, this is the common-mode output voltage. 

    You can also see the input to output voltage relationship by the figure I've pasted below from the datasheet. 

    VOUTN should not be directly connected to GND2 however. This is a driven output. Please add a 10kohm resistor between VOUTN and GND2 if you do not wish to use the differential output. Otherwise the device may be damaged. 

  • 0 in reply to Alexander Smith
    Prodigy 110 points

    Hi Alexander,
    Thanks for your assistance.
    I will implement the circuit.
    Thanks again.