The Designer's Guide Community
Forum
Welcome, Guest. Please Login or Register. Please follow the Forum guidelines. Oct 23rd, 2017, 3:44pm
  HomeHelpSearchLoginRegisterPM to admin  
 
Pages: 1
Send Topic Print
Giving an input DC bias current for an IC (Read 357 times)
Venky_analog
Junior Member
**
Offline

Analog Design is my
trade. Math is my
love.

Posts: 10
TX, USA
Giving an input DC bias current for an IC
May 31st, 2017, 6:25pm
 
Hi,

I am trying to give the DC bias current to an IC from an external source. The way I am generating this current is by using a potentiometer structure shown below.



By changing both VDD (tunable) and R1 (potentiometer), I can change the current. The VDD comes from an LDO and hence it's kind of accurate.

The thing is I placed another series resistor R2 to reduce the variations in the current due to possible variations in the potentiometer, as I heard potentiometers are very sensitive to their environments and tend to change with time a lot.

My quesiton is if I keep R2 like 25% of R1, would it be good enough? Also, is this a good way of generating current externally for biasing circuits inside an IC?

Thanks in advance
Back to top
 
 

Either die a white noise or live long enough to see yourself become the 1/f noise.
View Profile   IP Logged
kabir_fakir
Junior Member
**
Offline



Posts: 19

Re: Giving an input DC bias current for an IC
Reply #1 - Aug 30th, 2017, 4:50am
 
For me it looks fine. I am only concerned about the thermal noise of the resistor itself as you are introducing 2 rsistors
As I did testing with my IC too. to generate the dc current, I took a clean power supply (Agilent- E3644A) and put a huge resistor (in 10k range) in series with that (instead of potentiometer ). And then I keep varying the DC power supply as per requirement of the current.
Back to top
 
 

Always a learner and will be .
View Profile   IP Logged
Pages: 1
Send Topic Print
Trouble viewing this site? Copyright © 2002-2014 Designer's Guide Consulting. 'Designer's Guide' is a registered trademark of Designer's Guide LLC. All rights reserved.

Our colleges are not as safe as they seem. Sexual assault is pervasive and the treatment of the victim by the adminstration is often as damaging as the assault: Campus Survivors, Campus Survivors Forum.

Some of our other sites that you might find useful: QuantiPhy.