Power Supply Rejection in LTSpice

A

AsiongMartinez12

New Member
Hi. I am struggling in getting the power supply rejection in LTSpice. I am to design an LDO of regulated output of 0.8 with accuracy of +/- 2%. The power supply rejection is the only thing left. please help me get a 20dB PSR
 

Attachments

  • 1.png
    24.9 KB · Views: 483
The default MOSFETS aren't much use. Specify the actual MOSFET models and see what happens. Can you post your asc file?
 
Sorry, I've no experience of playing about with the FET parameters (I just pick a FET from a library). Perhaps someone else can help there.
 
EricGibbs and MikeMl, to name but two, are members with a lot more LTspice experience than me.
 
The power supply rejection is simply the output AC voltage versus input AC voltage (ripple).
Set the AC value to 1V in the input DC source, with an output resistive load sufficient to properly bias the circuit (the circuit you posted does not seem to tolerate any load).
Then do an a AC analysis, which will show how much the input voltage is attenuated at the output versus frequency (shown in dB).
 
AsiongMartinez12 said:
Hello crutschow what do you mean I dont have a load in my circuit.. Could you help me out on that part..
Click to expand...
True, you don't have a load on the amp.
And my simulation showed that it can't tolerate any load, which would seem to make the circuit rather useless.
 
Thanks, Asiong, for your belief that I could but as I said, I have no experience with using/choosing FET parameters (at the CMOS process level). I can't design the FETs themselves.
If you want a design using existing specific FET models included in the component library that comes with LTspice, then googling "low dropout regulator schematic" gives you many options to study and perhaps use as a basis.
It would help to know what course work your design brief is meant to be based on.
 
You must log in or register to reply here.

Similar threads

S
  • Question Question
LTspice How to view the RMS value of waveform for power dissipation in Waveform Viewer.
Replies
4
Views
3K
Lightium
G
  • Question Question
Computer power supply design
Replies
5
Views
1K
ahsrabrifat
A
M
9V DC Power Supply
Replies
5
Views
1K
mrob
M
C
  • Question Question
20W Power Supply for Stereo Amplifier
2
Replies
29
Views
3K
crutschow
D
  • Question Question
Building Bench power supply
Replies
0
Views
1K
drjackool
D
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…