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I use virtuoso cadence to make two bridge rectifier,one of them use NMOS to replace the diode,and the other use DION_MM directly,like the picture shown

enter image description here

But their simulation are wrong,like the picture below shown,and i want to ask where is my schematic wrong?the gnd position?The red line is the wave of right schematic,and the blue line is the left,and the black line is the alternating current voltage source

enter image description here

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  • \$\begingroup\$ Are the W/L ratios important to your circuit? I ask this because I cannot read these values on your schematic (even when I enlarge the pictures and zoom in). \$\endgroup\$ – KingDuken Mar 1 '18 at 15:42
  • \$\begingroup\$ you mean the DION_MM?if yes,i think the name will be different in the different process,i use the UMC18 \$\endgroup\$ – Shine Sun Mar 1 '18 at 15:42
  • \$\begingroup\$ I think not,because i just use the mos to replace the diode,like here:en.wikipedia.org/wiki/Voltage_multiplier \$\endgroup\$ – Shine Sun Mar 1 '18 at 15:44
  • \$\begingroup\$ It also use NMOS to replace the diode,and make the charge pump \$\endgroup\$ – Shine Sun Mar 1 '18 at 15:45
  • \$\begingroup\$ Active rectifiers need a driver IC for full ON voltage at the proper time. \$\endgroup\$ – Sparky256 Mar 4 '18 at 5:22
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But their simulation are wrong,like the picture below shown,and i want to ask where is my schematic wrong?the gnd position?

You need to place your circuit simulator's ground reference point on the bottom of the load resistor if you want to display the bridge rectified output as is normally presented.

Any sim will calculate the voltage at a node relative to the ground reference point and because you have yours on the AC output, you will not see the voltage directly across the load resistor.

If you want to simultaneously show the AC voltage pattern AND the bridge output then you need to use a "voltage controlled voltage source" conncted to one of the input voltages you want to display then, on the output of the VCVS, tie it to the ground reference point. Think of it like a differential amplifier but in-built into most sims: -

enter image description here

  • Red = input voltage relative to ground
  • Blue = output voltage relative to ground
  • Green = voltage across R1 re-referenced to ground so it can be viewed correctly
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  • \$\begingroup\$ you mean i need two ground?one for source,and one for load resistor?because i have tried that before,but if i do that,the simulation of output and the source are not correct \$\endgroup\$ – Shine Sun Mar 1 '18 at 16:08
  • \$\begingroup\$ You can only have one ground because multiple grounds will make connections in the simulation. Go look up VCVS in your simulator - it is the same as an ideal differential amplifier. \$\endgroup\$ – Andy aka Mar 1 '18 at 17:14
  • \$\begingroup\$ @Andyaka Putting a scope probe ground on the output of a non-isolated mains-connected bridge rectifier can illustrate the problem nicely :) \$\endgroup\$ – John D Mar 1 '18 at 18:56

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