Integrated low-corner frequency high pass filter circuit
AssigneeEM Micoelectronics-US, Inc
InventorsKevin Scott Buescher, James Harold Lauffenburger
Life of this patent
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Abstract
A low-corner frequency high pass filter circuit (10) includes an operational amplifier (12). The operational amplifier (12) has an inverting input (14) and a non-inverting input (24). A series capacitor (26) has a first end connected to the non-inverting input (24) of the operational amplifier (12). A second end of the series capacitor (26) is connected to an input signal (28). A low gain amplifier (30) has an input connected to an output (22) of the operational amplifier (12) and has an output (32) connected to the non-inverting input (24) of the operational amplifier (12). The low gain amplifier (30) performs the function of large value resistor.
Claims9
A low-corner frequency high pass filter circuit comprising:
- an operational amplifier having an inverting input, a non-inverting input and an output;
- a first resistor connected between the inverting input and a reference voltage;
- a feedback resistor connected between the inverting input and the output;
- a series capacitor having a first end connected to the non-inverting input of the operational amplifier and a second end connected to an input signal;
- and
- a low gain amplifier, having an input connected to the output of the operational amplifier and having an output connected to the non-inverting input of the operational amplifier, wherein the low gain amplifier includes a first amplifier having a first gain and a second amplifier having a second gain, a first amplifier output being subtracted from a second amplifier output, wherein the first gain is different than the second gain.
The circuit of claim of 1, wherein the first amplifier is a differential amplifier having a first input connected to a reference voltage and a second input connected to the output of the operational amplifier.
A low-corner frequency high pass filter circuit comprising:
- an operational amplifier having an inverting input and a non-inverting input;
- a series capacitor having a first end connected to the non-inverting input of the operational amplifier and a second end connected to an input signal;
- a switching network connected to the series capacitor;
- a parallel capacitor connected to the switching network;
- and
- a low gain amplifier having an input connected to an output of the operational amplifier and having an output connected to the non-inverting input of the operational amplifier.
The circuit of claim of 7, wherein the first amplifier is a differential amplifier having a first input connected to a reference voltage and a second input connected to the output of the operational amplifier.
Dependencies are inferred from the claim text.