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#1 Dec 14, 2016
tak
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How to FRA setting

How to FRA Setting

Please advised me how to set FRA.

I'd like to simulate FRA such as attached schematics(njm2377)(forward converter).

I don't know how to set following @pspice setting.

Please advised me!

Your prompt reply is highly appreciated.

Thank you in advance.

----------------------------------------------

@PSpice:
.TRAN  0 {5/Freq}
.STEP DEC PARAM FREQ 0.1 1MEG 7
.PROBE64 P(FREQ)
.options MINSIMPTS = 1000

 

 

Wed, 2016-12-14 09:14
mvaseem
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Hi Tak,

Need some more information in order to answer your question. Can you tell me below information so that I can provide FRA setup details -

1) In normal transient run, around what time the circuit reaches comfortably in steady state ?

2) What would be your frequency of interest for viewing frequency response ? I need your maximum frequency of interest.

Please let me know above answers.

 

Thanks,

Vaseem

Wed, 2016-12-14 10:00
tak
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Hi Vaseem

Thank you for your prompt reply.

Here is my reply.

1) about 1ms

2) from 1Hz to 100MHz

My reference FRA is following URL,but I could not understand how to set this.

@PSpice:
.TRAN  0 {5/Freq}
.STEP DEC PARAM FREQ 0.1 1MEG 7
.PROBE64 P(FREQ)
.options MINSIMPTS = 1000

https://www.youtube.com/watch?v=7RTaRqGtZKs

and my reference schematics( boost DC/DC Converter (NJM2377)) is following URL.

http://beetech.dgblog.dreamgate.gr.jp/e92109.html

Your prompt reply would be grately appriciated.

Thu, 2016-12-15 00:41
mvaseem
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Hi Tak,

First of all the source need to be inserted at a place in feedback path where it drives a high impedance. I am not able to attach image, but the net at bottom having bias voltage of 273mV is the one where I think you should insert the source. I am assuming the FB & -IN terminals of NJM2377 are inputs of a comparator (which are always high impedances).

The Spice directive on Capture should be as below -

@PSpice:

.param freq=1

.TRAN 0 {N/Freq+1m} 1m

.STEP OCT PARAM Freq 1 100Meg 3

.PROBE64 P(Freq)

.options MINSIMPTS=1000

Replace the value of N (in .TRAN statement) such that the transient run with highest freq sweep value consists of few cycles of PWM switching oscillator. I notice you are using 10KHz switching freq. In order to have 5 cycles with highest freq as 100MHz, you need value of N=50000. This would make the simulation infinitely long.

I think you should reduce the frequency band of interest in order to resolve the above issue. With reduced band 10KHz ->10Meg, the new statement would be as below -

.TRAN 0 {5000/Freq+1m} 1m

.STEP OCT PARAM Freq 10K 10Meg 3

Other directives remain same. This should not take very long time to simulate.

Please see if above works.

Thu, 2016-12-15 05:33
tak
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Hi Vaseem

Thank you very much for your prompt reply!

I will try your advice.

Thank you in advance.

Thu, 2016-12-15 09:17
tak
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Hi Vaseem

Could you please advise me how to edit dat file to simulate FRA.

I start simulation,then click FRA bottom of tool bar,I cold not find dat file.

OrCad lite 16.6 is not available FRA?

Please let me know if you know about this.

Thank you in advance.  

Thu, 2016-12-15 09:48
mvaseem
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Hi Tak,

Yes FRA ac.dat file does not load with Lite version of software.

This is limitation in current flow.

Thu, 2016-12-15 19:14
tak
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Hi Vaseem

Thank you for your reply.

I wll try to solve this issu another way...

Fri, 2018-06-29 03:43
vv443
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The free roblox robux is now available on http://onlinefreerobux.com/ for free.

Wed, 2018-07-18 15:48
alexandar
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Wed, 2018-07-18 15:49
alexandar
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Wed, 2018-07-18 15:49
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Wed, 2018-07-18 15:51
alexandar
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