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Design >> Analog Design >> 2 pole low frequency shelving filter design
https://designers-guide.org/forum/YaBB.pl?num=1423321888

Message started by Northy on Feb 7^th, 2015, 7:11am

Title: 2 pole low frequency shelving filter design
Post by Northy on Feb 7^th, 2015, 7:11am

Hi,

I'm trying to design a 2 pole low frequency shelving filter to boost the low frequencies in an audio circuit.

I've modeled this circuit and it models correctly, but I want to run it on a single supply op amp (LM324).

Should I connect R15 and R16 to 1/2 the supply voltage to make it work correctly?

Thanks,

Northy

Title: Re: 2 pole low frequency shelving filter design
Post by Rakesh on Feb 7^th, 2015, 3:56pm

Hi,
Check the output common mode voltage. Connect the resistors to that value. yes typically you need to connect the resistors to vdd/2.
Rakesh

Title: Re: 2 pole low frequency shelving filter design
Post by Northy on Feb 9^th, 2015, 12:17pm

This is the circuit that I'm playing with at the moment. It seems to work if I feed about 0.5V into V_Bias. I'm confused why it is only 0.5V though.

Thanks,
Northy