초록 ▼

A circuit and method for adjusting a cutoff frequency of an active filter, such as a gm-C filter, which has a common mode feedback circuit for providing a bias signal may include plural common base stages having first inputs connected in parallel to a stage of the active filter and second inputs con

A circuit and method for adjusting a cutoff frequency of an active filter, such as a gm-C filter, which has a common mode feedback circuit for providing a bias signal may include plural common base stages having first inputs connected in parallel to a stage of the active filter and second inputs connected in parallel to an output from the common mode feedback circuit, and a capacitor connected to an output from each of the common base stages. The common base stages and their connected capacitors are selectively isolated from the filter output to adjust the cutoff frequency of the filter. The deselected common base stages are also isolated from the common mode feedback circuit and bias generator inputs.

대표청구항 ▼

A gm-C filter comprising: a gm stage for receiving an input signal and for providing an output signal; a common mode feedback circuit for providing a bias to maintain a DC component of an output voltage of said output signal from said gm stage at a reference level; plural common base stages, each ha

A gm-C filter comprising: a gm stage for receiving an input signal and for providing an output signal; a common mode feedback circuit for providing a bias to maintain a DC component of an output voltage of said output signal from said gm stage at a reference level; plural common base stages, each having a first input connected to said gm stage and a second input connected to said common mode feedback circuit; and plural first switches, each connected to at least one of said plural common base stages for selectively connecting said at least one of said common base stages to an output of said gm-C filter to control a tuning range of the gm-C filter.