An apparatus and method for a frequency based integrated circuit that selectively filters out unwanted bands or regions of interfering frequencies utilizing one or more tunable notch or bandpass filters or tunable low or high pass filters capable of operating across multiple frequencies and multiple bands in noisy RF environments. The tunable filters are fabricated within the same integrated circuit package as the associated frequency based circuitry, thus minimizing R, L, and C parasitic values, and also allowing residual and other parasitic impedance in the associated circuitry and IC package to be absorbed and compensated.

A high-order filter with a capacitive inner tapping technique is disclosed. The filter includes an inductor and a first resonant circuit including a first portion of the inductor and a first capacitor. The first resonant circuit is configured to attenuate first frequency components of an input signal above a cutoff frequency to generate a filtered signal. The filter further includes a second resonant circuit coupled in parallel with the first resonant circuit and including the first portion of the inductor and a second capacitor. The second resonant circuit is configured to attenuate the first frequency components of the input signal to generate the filtered signal. A third resonant circuit includes a second portion of the inductor and a third capacitor, wherein the third resonant circuit is configured to attenuate second frequency components of the filtered signal above the cutoff frequency to generate an output signal.

An electronic device may include wireless circuitry having an LC filter. The LC filter may include first and second series inductors coupled between the input and output of the LC filter. An input capacitor can be coupled at the input of the LC filter, and an output capacitor can be coupled at the output of the LC filter. Feedforward capacitors can be cross-coupled with the first and second series inductors to at least partially or fully cancel out any parasitic capacitance associated with the first and second series inductors to mitigate any undesired self-resonant effects associated with the series inductors.

A radio-frequency filter (10) includes a series arm circuit (11) and a parallel arm circuit (12). The series arm circuit (11) is disposed on a path connecting an input/output terminal (11m) and an input/output terminal (11n). The parallel arm circuit (12) is connected to a ground and to a node (x1) on the path. The series arm circuit (11) includes a series connecting circuit (11e) and a first variable frequency circuit (11a). The series connecting circuit (11e) includes a series arm resonator (S1) and a capacitor (C1). The first variable frequency circuit (11a) is connected in parallel with the series connecting circuit (11e) and varies the anti-resonant frequency of the series arm circuit (11). The first variable frequency circuit (11a) includes a capacitor (C2) and a switch (SW1) connected in series with each other. The series arm resonator (s1) and the capacitor (C1) are connected in series with each other.

A device can include a thin-film bulk acoustic resonator (FBAR), a transceiver, a capacitor network, and a processor. The transceiver can transmit and receive radio frequency (RF) signals using the FBAR. The capacitor network can be conductively coupled to the FBAR. The processor can be in communication with the capacitor network. The processor can obtain a capacitor tuning code. The processor can further establish a capacitance of the capacitor network based on the capacitor tuning code during a RF receiving operation.

A flexible multi-path RF adaptive tuning network switch architecture that counteracts impedance mismatch conditions arising from various combinations of coupled RF band filters, particularly in a Carrier Aggregation-based (CA) radio system. In one version, a digitally-controlled tunable matching network is coupled to a multi-path RF switch in order to provide adaptive impedance matching for various combinations of RF band filters. Optionally, some or all RF band filters include an associated digitally-controlled filter pre-match network to further improve impedance matching. In a second version, some or all RF band filters coupled to a multi-path RF switch include a digitally-controlled phase matching network to provide necessary per-band impedance matching. Optionally, a digitally-controlled tunable matching network may be included on the common port of the multi-path RF switch to provide additional impedance matching capability. In a third version, CA direct mapped adaptive tuning networks include filter tuning blocks for selected lower frequency bands.

A tunable passband filter including a signal input port for receiving an input radio frequency (RF) signal, a signal output port for transmitting a filtered output RF signal, a first high-pass section having a first tunable microelectromechanical system (MEMS) switch array to receive the input RF signal from the signal input port, a second high-pass section having a second tunable MEMS switch array to transmit the output RF signal to the signal output port, and a low pass section operatively coupled between the first high-pass section and the second high-pass section, and having each of a first tunable MEMS bridge array, a second tunable MEMS bridge array, and a high impedance line. The tunable passband filter is configured to filter the input RF signal to yield the filtered output RF signal.

An apparatus and method for a frequency based integrated circuit that selectively filters out unwanted bands or regions of interfering frequencies utilizing one or more tunable notch or bandpass filters or tunable low or high pass filters capable of operating across multiple frequencies and multiple bands in noisy RF environments. The tunable filters are fabricated within the same integrated circuit package as the associated frequency based circuitry, thus minimizing R, L, and C parasitic values, and also allowing residual and other parasitic impedance in the associated circuitry and IC package to be absorbed and compensated.

A capacitance adjustment method for enabling or disabling a first set of capacitors to an n.sub.th set of capacitors of n sets of capacitors, includes generating a base count according to base capacitance, generating a first count to an n.sub.th count according to the first set of capacitors to the n.sub.th set of capacitors respectively, obtaining a first ratio to an n.sub.th ratio according to the base count and the first count to the n.sub.th count, indicating a target count, obtaining a target ratio according to the base count and the target count, and obtaining a first control signal to an n.sub.th control signal according to the target ratio and the first ratio to the n.sub.th ratio so as to enable or disable the first set of capacitors to the n.sub.th set of capacitors accordingly.

An adaptive logic board for a variable speed drive (VSD) of a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a signal sensing circuit configured to receive an input signal from a sensor of the VSD. The signal sensing circuit includes a filter configured to condition the input signal. The filter includes a variable resistance element configured to adjust a cutoff frequency of the filter. The filter is configured to attenuate waveforms in the input signal having frequencies that exceed the cutoff frequency to generate a conditioned signal. The adaptive logic board also includes a controller configured to receive the conditioned signal and to adjust the variable resistance element to adjust the cutoff frequency of the filter based on a parameter of the HVAC&R system.