The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Design >> Analog Design >> The limitation of digital compensation circuit
https://designers-guide.org/forum/YaBB.pl?num=1277280630

Message started by casual on Jun 23^rd, 2010, 1:10am

Title: The limitation of digital compensation circuit
Post by casual on Jun 23^rd, 2010, 1:10am

A compensation circuit senses the delta difference between d+ & d- and then uses a DAC to compensate d+ & d- until it has 101010 patterns at the comparator output (conventional digital compensation circuit).

The drawback of this circuit is that it does not know which compensation codes is the closest to the zero difference (assume no glitch) since the analog value cannot be stored.

is there a way to know which code is the best code? the present code or the previous code?

Title: Re: The limitation of digital compensation circuit
Post by vivkr on Jun 23^rd, 2010, 1:56am

What you would need is either an analog correction circuit or a higher resolution digital correction circuit (which is "analog" for your coarse 1-bit corrector) parallel to the digital correction which you are using. This needs only a smaller range.

What are you trying to correct for by the way?

Vivek

Title: Re: The limitation of digital compensation circuit
Post by Mayank on Jun 23^rd, 2010, 3:51am

Quote:

is there a way to know which code is the best code? the present code or the previous code?

Forget what is closest to the Actual Value. This is the funda of Digital Calibration.
You set your resolution acc. to max. error you can tolerate.
After that, you just have to accept one or two bit error depending on your scheme.
Resolving / Rounding off final code requires Delta/2 comparison, which again means higher resolution either in analog OR Digital cktry --> Hardware Overhead.

Title: Re: The limitation of digital compensation circuit
Post by casual on Jun 23^rd, 2010, 4:23am

exactly same as what I was thinking...

;D