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LMP7300: Detecting rectified AC (450V ) over voltage.

Part Number: LMP7300
Other Parts Discussed in Thread: TLV6713, TLV6703

Hi Team 

I am making one AC overvolatge indicator. Basically we want to glow LED after AC voltages increases configurable over volatge. Can i uses LMP7300 

as  below for same.sch_OVP.pdf

  • Abhishek

    Unfortunately the circuit implementation you shared will not work.  The LMP7300 input common-mode voltage range is from1 V above the negative rail to, and including,the positive rail.  Generally the REF pin or a resistor divided down version of the REF is connected to one of the inputs of the comparator.

    The LMP7300 is quite a specialized part and I am not certain that is the best option for your application.  Since you have a resistor drop in the supply line, you need to be very cautious about the operating current of the comparator as well.  The way you have your circuit drawn, the power supply for the comparator is derived from a resistive pot of 100k and a 4.7k resistor.  That is fine for the input of the comparator to monitor but that may not be the best option for powering your comparator.  I would recommend some sort of shunt regulator if possible to make the supply voltage more stable.  It is possible that the scheme you are proposing can work as the power supply but I would be concerned about the high and low range while the comparator is operating.

    If you still feel a comparator with integrated reference is required for your circuit, the TLV6703 operates up to 18V and the TLV6713 operates up to 36V.  Otherwise, if you regulate your supply for the comparator, you can derive your reference from that voltage and use a simple low power comparator.


  • Abhishek

    There has not been any response on this thread for a while, so I will be closing this post.  If you need further assistance, please open a new thread or reply to this one.