Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic 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.

Register Log in

Frequency Compensation

Status
Not open for further replies.

ambreesh

Full Member level 5
Joined
Feb 21, 2005
Messages
319
Helped
21
Reputation
42
Reaction score
4
Trophy points
1,298
Activity points
4,347
Can someone tell me how we can insert a LHS zero in a system?
 

amarnath

Advanced Member level 1
Joined
Apr 24, 2003
Messages
402
Helped
25
Reputation
50
Reaction score
7
Trophy points
1,298
Activity points
3,141
Just add a miller cap as in a two stage opamp, this will introduce a zero since you now create another path for the signal to reach the output.Then try moving this zero to the right half if needed to improve your phase margin.

amarnath
 

lijianheng

Full Member level 2
Joined
Sep 29, 2006
Messages
125
Helped
13
Reputation
26
Reaction score
5
Trophy points
1,298
Activity points
1,826
Insert a resistor in series with the compensation capacitor.
 

amarnath

Advanced Member level 1
Joined
Apr 24, 2003
Messages
402
Helped
25
Reputation
50
Reaction score
7
Trophy points
1,298
Activity points
3,141
The resistor nullfies the zero if its sized such that it cancels out the zero created by the miller cap. The resistor can also be sized to move the zero to the right half plane to increase the phase margin.


amarnath
 

ambreesh

Full Member level 5
Joined
Feb 21, 2005
Messages
319
Helped
21
Reputation
42
Reaction score
4
Trophy points
1,298
Activity points
4,347
Yes, method of nulling resistor along with the cap in series is know well.
But do we have any alternate method of adding LHZ.

I think it was a typing mistake , we would not like the zero to be RHS as it is going to deteroriate te phase margin.
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top