How does this circuit work?

[Syafiq]

Hi

How does this Switch Capacitor Filter circuit work? I am a bit confused by the way it operates. Thanks!

 

[Pommie]

Me too!!!

Mike.

 

[Syafiq]

I got this from an internet source.

 

[Willen]

Hi

How does this Switch Capacitor Filter circuit work? I am a bit confused by the way it operates. Thanks!

Mee too! But aren't they manual (analog) input and feedback switch with decoupling capacitor? hehehe

 

[audioguru]

None of the Switched capacitor Filter articles I found in Google has the schematic you showed.

 

[audioguru]

Here is the schematic of the filter in an actual IC and shown in nearly all articles about it in Google:

 

[Syafiq]

Here is the schematic of the filter in an actual IC and shown in nearly all articles about it in Google:

I got it from here :**broken link removed**

 

[crutschow]

No wonder it's confusing. Your circuit is not the same as the circuit in the article.

 

[audioguru]

No wonder it's confusing. Your circuit is not the same as the circuit in the article.

No.
It is exactly the same circuit except two of his switches are turned on.

 

[Syafiq]

No.
It is exactly the same circuit except two of his switches are turned on.

So the circuit in the article is correct right? But why are all his switches turned on? In my circuit, there are 2 pairs of switches "phi1" and "phi2". They are controlled by a non-overlapping clock hence when "phi1" is on, "phi2" is off.

 

[audioguru]

So the circuit in the article is correct right? But why are all his switches turned on? In my circuit, there are 2 pairs of switches "phi1" and "phi2". They are controlled by a non-overlapping clock hence when "phi1" is on, "phi2" is off.

All the switches in the article are turned off (open) to show that they are switches and not continuous wires. I agree with you that they should be switched in pairs.