Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

PSRR simulation for Bandgap Reference.

Status
Not open for further replies.

snoop835

Advanced Member level 4
Joined
Feb 7, 2005
Messages
102
Helped
6
Reputation
12
Reaction score
3
Trophy points
1,298
Location
Penang, Malaysia
Activity points
1,370
psrr simulation

Hi guys,

I am new in Bandgap Reference design. Currently I need to investigate the performance of Bandgap Voltage Reference using 1.8V supply. I have run DC sweep and temperature sweep to see its variation across temperature and supply voltage. My question is how to simulate for PSRR? What is the testbench setup for this? Is it in AC analysis or DC analysis? Can anyone suggest me good references or articles on this. I am also looking for good reading materials on Bandgap Reference.

Appreciate your help in advance....cheers

-snoop835-
 

gdhp

Advanced Member level 4
Joined
Jan 7, 2005
Messages
116
Helped
2
Reputation
4
Reaction score
1
Trophy points
1,298
Activity points
931
site:edaboard.com bandgap psrr

an 'ac' siganl at power, run the simulation of ac.

i think the psrr of bg is simialr with the opamp. you can do some reading on the the book of allen.
 

    snoop835

    Points: 2
    Helpful Answer Positive Rating

snoop835

Advanced Member level 4
Joined
Feb 7, 2005
Messages
102
Helped
6
Reputation
12
Reaction score
3
Trophy points
1,298
Location
Penang, Malaysia
Activity points
1,370
psrr bandgap simulation

Thanks for the hint gdhp.

Here's the simulation waveforms that I have got after I run ac analysis. I think the result is acceptable. Can somebody tell me why is it in negative dB? Please give comments on this waveform.
 

Humungus

Full Member level 6
Joined
Jul 10, 2001
Messages
384
Helped
41
Reputation
82
Reaction score
15
Trophy points
1,298
Activity points
3,985
bandgap reference simulation

It is very important to keep in mind that PSRR (as well as CMRR) is made of two terms: sywtematic and random. When you perform a simple AC simulation, you'll only see the systematic (which in theory can be corrected) PSRR. Actually, PSRR arises from mismatches among the different signal paths from any source rail to the output. If everything were symmetric, PSRR would be negligeable. So, perfom and AC simulation, but along with a Monte Carlo analysis.
 

    snoop835

    Points: 2
    Helpful Answer Positive Rating

drabos

Full Member level 6
Joined
Jan 3, 2006
Messages
399
Helped
45
Reputation
90
Reaction score
15
Trophy points
1,298
Activity points
3,754
Re: psrr bandgap simulation

Thanks for the hint gdhp.

Here's the simulation waveforms that I have got after I run ac analysis. I think the result is acceptable. Can somebody tell me why is it in negative dB? Please give comments on this waveform.

plot the dB(1/vref)
 

yuvan

Member level 4
Joined
Apr 27, 2012
Messages
72
Helped
10
Reputation
20
Reaction score
10
Trophy points
1,288
Activity points
1,681
Humungus,
As far as it in a loop the random offset doesn't contribute a lot unless in the feedback. And in this case it is mostly the PMOS the current source in f/b (and also if the opamp gain is too low), so random variation in them shouldn't cause to much of an effect unless the deviation is too big for the positive gain to dominate.
And I think the PSRR shown is bit less & could be increased too, since the supply is 1.8v & we have 0.7v headroom (I guess u r trying to regulate the output to 1.1)
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top