Patent ID: 7327997

Claim:
A trans_impedance filter circuit processing an input signal and generating an output signal, said trans_impedance filter circuit comprising: an operational amplifier having an inverting input terminal, a non_inverting input terminal and an output path; a first resistor having one terminal coupled to receive said input signal, and another terminal being coupled to said inverting input terminal; a first capacitor being coupled between said one terminal of said first resistor and a first constant bias; a second resistor connected between a first node and said output path, wherein said first node is in a path said input signal is provided to said inverting input terminal; and a second capacitor connected between said inverting input terminal and said output path; further comprising: a third resistor connected in series with said first resistor at a second node, wherein said another terminal of said third resistor is connected to receive said input signal at said first node; a third capacitor and a fourth capacitor connected in series between said first node and said inverting input terminal, said third capacitor being connected to said fourth capacitor at a third node; and a fourth resistor being connected between said third node and a third constant bias.