A proximity sensor that detects the distance between two coils is disclosed. In one example, the proximity sensor includes a reference signal generation circuit, a first coil, a second coil, a clock signal generation circuit, and a switched capacitor circuit. The reference signal generation circuit applies a first alternating voltage to the first coil and transmits a reference signal synchronized with the first alternating voltage to the clock signal generation circuit. The second coil is coupled with the first coil by magnetic field coupling to generate a second alternating voltage correlated with a coupling coefficient. The clock signal generation circuit transmits clock signals corresponding to the reference signal to the switched capacitor circuit, and the switched capacitor circuit detects a distance between the first coil and the second coil by acquiring the second alternating voltage at a timing when each of the clock signals changes.

Phase-locked loop circuitry to generate an output signal, the phase-locked loop circuitry comprising oscillator circuitry, switched resistor loop filter, coupled to the input of the oscillator circuitry (which, in one embodiment, includes a voltage-controlled oscillator), including a switched resistor network including at least one resistor and at least one capacitor, wherein an effective resistance of the switched resistor network is responsive to and increases as a function of one or more pulsing properties of a control signal (wherein pulse width and frequency (or period) are pulsing properties of the control signal), phase detector circuitry, having an output which is coupled to the switched resistor loop filter, to generate the control signal (which may be periodic or non-periodic). The phase-locked loop circuitry may also include frequency detection circuitry to provide a lock condition of the phase-locked loop circuitry.

A sensor device includes: first sensors; second sensors which form capacitances with the first sensors; a sensor transmitter connected to the first sensors, where the sensor transmitter supplies driving signals to the first sensors; and a sensor receiver connected to the second sensors, where the sensor receiver receives sensing signals from the second sensors, and the sensor receiver includes a band pass filter which filters the sensing signals. The band pass filter includes: a first integrator including a first amplifier; a first high pass filter converter connected to a first input terminal, a second input terminal and a first output terminal of the first amplifier, where the first high pass filter converter time-divisionally provides N high pass filter conversion paths; and a first gain auxiliary component connected to the first input terminal and the first output terminal of the first amplifier while the first integrator performs an integral function.

An adaptive capacitive filter circuit includes: a first terminal adapted to be coupled to a rectifier bridge output; a second terminal adapted to be coupled to a ground terminal; a first capacitor having a first electrode and a second electrode, the first electrode of the first capacitor coupled to the first terminal; a second capacitor having a first electrode and a second electrode, the second electrode of the second capacitor coupled to the second terminal; a first switch coupled between the second electrode of the first capacitor and the second terminal; a second switch coupled between the first terminal and the first electrode of the second capacitor; and a third switch coupled between the second electrode of the first capacitor and the first electrode of the second capacitor.

A variable circuit includes a switch including a plurality of input terminals and a plurality of output terminals and an external wiring line. The multiple input terminals include a first input terminal to which a first input signal is inputted and a second input terminal to which a second input signal is inputted. The multiple output terminals include a first output terminal from which a first output signal is outputted and a second output terminal from which a second output signal is outputted. The switch is capable of forming at least one internal connection path electrically connecting any one of the multiple input terminals and any one of the multiple output terminals. The external wiring line is disposed outside the switch and is configured to electrically connect the second output terminal to the second input terminal.

A system and method for providing asymmetrical filtering to improve performance in the presence of wideband interference is herein disclosed. According to one embodiment, a method for a global navigation satellite system (GNSS) receiver includes detecting wideband interference in a received target GNSS signal, and applying an asymmetric filter to the received target GNSS signal to mitigate the detected wideband interference.

A proximity sensor that detects the distance between two coils is disclosed. In one example, the proximity sensor includes a reference signal generation circuit, a first coil, a second coil, a clock signal generation circuit, and a switched capacitor circuit. The reference signal generation circuit applies a first alternating voltage to the first coil and transmits a reference signal synchronized with the first alternating voltage to the clock signal generation circuit. The second coil is coupled with the first coil by magnetic field coupling to generate a second alternating voltage correlated with a coupling coefficient. The clock signal generation circuit transmits clock signals corresponding to the reference signal to the switched capacitor circuit, and the switched capacitor circuit detects a distance between the first coil and the second coil by acquiring the second alternating voltage at a timing when each of the clock signals changes.

An apparatus includes a differential current-to-voltage conversion circuit that includes an input sampling stage circuit, a differential integration and DC signal cancellation stage circuit, and an amplification and accumulator stage circuit. An input common mode voltage of the differential current-to-voltage circuit is independent of an output common mode voltage of the differential current-to-voltage circuit.

A PFM control circuit includes a switching circuit, a slope-decision circuit, a flip-flop, a first and a second comparison circuits. The first comparison circuit outputs a first signal according to an output voltage of a power conversion circuit. The switching circuit outputs a switching signal according to an output current of the power conversion circuit. The slope-decision circuit outputs a slope modulation voltage, and determines a slope modulation voltage with a first or a second slope according to the switching signal. The second comparison circuit outputs the second signal according to the slope modulation voltage. The flip-flop outputs a control signal to the power conversion circuit according to the first and the second signals. When the slope modulation voltage has the first or the second slope, the control signal has a first or a second frequency accordingly. The first frequency is higher than the second frequency.

An adaptive capacitive filter circuit includes: a first terminal adapted to be coupled to a rectifier bridge output; a second terminal adapted to be coupled to a ground terminal; a first capacitor having a first electrode and a second electrode, the first electrode of the first capacitor coupled to the first terminal; a second capacitor having a first electrode and a second electrode, the second electrode of the second capacitor coupled to the second terminal; a first switch coupled between the second electrode of the first capacitor and the second terminal; a second switch coupled between the first terminal and the first electrode of the second capacitor; and a third switch coupled between the second electrode of the first capacitor and the first electrode of the second capacitor.