100/-100V square wave generator from 170AC source

Discussion in 'The Projects Forum' started by jy7w, May 13, 2014.

  1. jy7w

    Thread Starter New Member

    May 13, 2014
    Hi all,

    The goal is to generate a +/- 100V square wave from a 120 VAC wall source.
    In addition, I need to be able to control the frequency and amplitude from a microcontroller.

    I'm currently using a half rectifier and capacitor circuit to create the +/- 100V and feeding that into a comparator op-amp and using a signal from my micro to switch the output. However the problem is that the +/- 100V signal is referenced to NAC while the signal from my micro is referenced to GND from a voltage regulator and the comparator will have to be referenced to both GND and NAC which probably isn't a good idea.

    If anyone has any suggestions or a new solution, please let me know.
  2. wayneh


    Sep 9, 2010
    You should have read the Terms of Service you agreed to:

    "6. Restricted topics. The following topics are regularly raised however are considered "off-topic" at all times and will result in Your thread being closed without question:
    Any kind of over-unity devices and systems
    Automotive modifications
    Devices designed to electrocute or shock another person
    LEDs to mains
    Phone jammers
    Rail guns and high-energy projectile devices
    Transformer-less power supplies"
  3. AnalogKid

    Distinguished Member

    Aug 1, 2013
    What is the frequency range, and how much power does the waveform have to deliver? It it's not huge, get a whatever-sized power transformer with dual 70V secondaries (Signal, Prem, etc). This plus a bridge and two caps will get you +/-100VDC, isolated and power-limited. Your uC GND ties to the xfmr center tap. Add isolated gate drivers and some high voltage MOSFETs and you're good to go.

    Last edited: May 14, 2014