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TLV7011: Zero Crossing Detection with common mode voltage below VEE

Rico Schmitt73
Prodigy 100 points
Part Number: TLV7011
Other Parts Discussed in Thread: LM393-N

Hello,

i would like to switch my current zerocrossing detection circuit for a better, more precise, one. So i thought about doing something like this:

Taken from https://www.ti.com/lit/an/snoa999/snoa999.pdf

The design notes recommend the TLV7011 because of its phase inversion protection feature when leaving the CMVR. Is the no other comparator with a greater CMVR or a small workaround to stay within the CMVR, but keep getting precise ZC Events?

Has anyone tested a circuit like that?

  • 0
    Guru 140200 points

    Hi Rico,

    there are dozens of ways to build a zero crossing detector. You can use optos, transistors or the circuit shown in figure 31 of datasheet of LM393-N.

    What is your input signal? And what do you mean by "more precise"?

    Kai

  • 0 in reply to kai klaas69
    Prodigy 100 points

    kai klaas69 said:
    What is your input signal?

    Simple sinus waveform

    kai klaas69 said:
    And what do you mean by "more precise"?

    I want to minimize the delay between zero crossing and the zero crossing detection

    Right now i am using a simple circuit like this:

    But the delay between zero crossing and the detection is very long. I could optimize the circuit by getting rid of the voltage divider and instead use a zener diode, but there is also a assymmetry in the detection.

    kai klaas69 said:
    You can use optos, transistors or the circuit shown in figure 31 of datasheet of LM393-N.

    This one looks nice, if i get it right the 100k pull up resistor on the negative input is used to trim the input signal to minimize the time delay. Very smart.

  • 0 in reply to Rico Schmitt73
    TI__Mastermind 24480 points
    Rico
    If any further assistance is required on this post, feel free to reply. In the meantime I will be closing this post.
    Chuck