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#1 May 7, 2020
vignesht09
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Last seen: 4 years 5 months ago
Joined: 2020-04-29 04:16

Phase & Gain Margin

Hi,

How to capture Gain Margin & Phase margin for DC DC regulator

Currently i am trying to run AC analysis but not seeing any plot in simulation window?

What am i missing here?

 

Thanks

Thu, 2020-05-07 18:27
spice_up_your_c...
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Last seen: 4 years 4 months ago
Joined: 2020-01-26 09:49

Hi Vignesh,

Try this after running your AC simulation,

Add advanced markers on the schematic load/output to plot bode plot directly. They can be accessed by option PSpice from toolbar > Markers > advanced > db magnitude of voltage, phase magnitude of voltage and others

Below is a random example ckt. showing advanced markers placed on the schematic,

1_0.PNG

 

2_0.PNG

Now you should be able to make gain and phase margin measurments for your design 

Also, from the graph you may see that phase is plotted on a different Y-axis. Go to plot > Add Y-axis after plotting the graph for gain, and then plot the phase graph 

Tue, 2020-07-07 13:13
jasontnguyen
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Last seen: 2 years 2 months ago
Joined: 2018-01-28 10:29

A  DC-C regulator has a feedback voltage divier circuit which used to compare with a reference voltage. Add an AC injection source from the output voltage to the top resistor. Use dB Magnitude Probe to measure the Gain between the two nodes of the  AC injection source. Use dB Phase Probe to  measure the Phase across the AC injection source

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