A batteryless wireless sensor system includes a data acquisition system, a radio frequency (RF) transceiver, and a batteryless wireless sensor device. The RF transceiver is in communication with the data acquisition system, transmits a RF signal, and receives sensor data and provide the sensor data to the data acquisition system. The batteryless wireless sensor device includes a RF transmitter, an analog to digital converter (ADC), and a sensor. The batteryless wireless sensor harvests energy from the RF signal and generates a DC signal based on the energy harvested from the RF signal, powers up and operates the ADC and the sensor based on the DC signal, and generates sensor data. The batteryless wireless sensor then transmits the sensor data via the RF transmitter to the RF transceiver. In certain examples, the ADC is implemented as a current mode ADC.

A batteryless wireless sensor system includes a data acquisition system, a radio frequency (RF) transceiver, and a batteryless wireless sensor device. The RF transceiver is in communication with the data acquisition system, transmits a RF signal, and receives sensor data and provide the sensor data to the data acquisition system. The batteryless wireless sensor device includes a RF transmitter, an analog to digital converter (ADC), and a sensor. The batteryless wireless sensor harvests energy from the RF signal and generates a DC signal based on the energy harvested from the RF signal, powers up and operates the ADC and the sensor based on the DC signal, and generates sensor data. The batteryless wireless sensor then transmits the sensor data via the RF transmitter to the RF transceiver. In certain examples, the ADC is implemented as a current mode ADC.

An exemplary incremental two-step capacitance-to-digital converter (CDC) with a time-domain sigma-delta modulator (TDΔΣM) includes a voltage-controlled oscillator (VCO)-based integrator that can be used in a low-order loop configuration. Example prototypes are disclosed, which when fabricated in 40-nm CMOS technology, provides CDC resolution of 0.29 fF while dissipating only 0.083 nJ per conversion.

A SAR ADC (50) is disclosed. It comprises a differential input port having a first input (V.sub.inP) configured to receive a first input voltage and a second input (V.sub.inN) configured to receive a second input voltage, of opposite polarity compared with first input voltage. Furthermore, it comprises a (300) having a first sub circuit (310P) comprising a first plurality of capacitors (2C.sub.u, C.sub.u), each connected to a common node (320P) of the first sub circuit (310P) with a first terminal, and a second sub circuit (310N) comprising a second plurality of capacitors (2C.sub.u, C.sub.u), each connected to a common node (320N) of the second sub circuit (310N) with a first terminal. For each capacitor (2C.sub.u, C.sub.u) of the first plurality of capacitors, the first sub circuit (310P) comprises a first switch (S4) connected between the first input (V.sub.inP) of the SAR ADC and a second terminal of that capacitor, a second switch (S.sub.2) connected between a first reference-voltage input (V.sub.rP) and the second terminal of that capacitor, a third switch (S.sub.1) connected between a second reference-voltage input (V.sub.rN) and the second terminal of that capacitor, and a capacitive device (X.sub.P) connected between the second input (V.sub.inN) of the SAR ADC and the second terminal of that capacitor. The second sub circuit is arranged in a similar way.

Systems and methods related to successive approximation register (SAR) analog-to-digital converters (ADCs) are provided. A method for performing successive approximation registers (SAR) analog-to-digital conversion includes comparing, using a comparator, a first digital-to-analog (DAC) output voltage to a sampled analog input voltage to generate a comparison result including a first positive output and a first negative output; and gating, using gating logic circuitry, at least one of the first positive output or the first negative output of the comparator to next logic circuitry, the gating based at least in part on a digital feedback comprising information associated with at least one of an opposite polarity of the first positive output or an opposite polarity of the first negative output.

High speed, high dynamic range SAR ADC method and architecture. The SAR DAC comparison method can make fewer comparisons with less charge/fewer capacitors. The architecture makes use of a modified top plate switching (TPS) DAC technique and therefore achieves very high-speed operation. The present disclosure proffers a unique SAR ADC method of input and reference capacitor DAC switching. This benefits in higher dynamic range, no external decoupling capacitory requirement, wide common mode range and overall faster operation due to the absence of mini-ADC.

An analog-to-digital converter (ADC) includes a first comparator configured to generate a first comparison signal on a basis of a first asynchronous clock signal generated from a sampling clock signal, and a second comparator configured to generate a second comparison signal on a basis of a second asynchronous clock signal generated by a first comparison operation completion signal. The ADC includes a first control logic configured to output a first control signal on a basis of the first comparison signal and a second control logic configured to output a second control signal on a basis of the second comparison signal. The ADC includes a first reference signal adjusting circuit configured to adjust a first reference signal on a basis of the first control signal and a second reference signal adjusting circuit configured to adjust a second reference signal on a basis of the second control signal.

Describe is a buffer which comprises: a differential source follower coupled to a first input and a second input; first and second current steering devices coupled to the differential source follower; and a current source coupled to the first and second current steering devices. The buffer provides high supply noise rejection ratio (PSRR) together with high bandwidth.

An analog-to-digital converter (ADC) and an operation method thereof are provided. The ADC includes: a comparator which compares a signal input through a first input terminal and a signal input through a second input terminal, and outputs an output value according to the comparison result. A successive approximation register receives the output value of the comparator, sets digital signal values from a most significant bit to a least significant bit, and outputs the digital signal values. A digital-to-analog converter receives the digital signal values, and converts it into an analog signal based on a reference voltage Vref, and outputs it to the second input terminal. A noise component is added to the input signal and to the analog signal Vdac′.

Analog calibration (ACAL) circuits supporting iterative measurement of an input signal from a measured circuit, and related methods are disclosed. The ACAL circuit includes a voltage reference generation circuit and a comparator circuit. The voltage reference generation circuit is configured to provide an input reference voltage. The comparator circuit is configured to compare the input reference voltage to an input circuit voltage of a measured circuit and generate a digital measurement signal based on the comparison. To provide for the ACAL circuit to more precisely measure the input circuit voltage, the voltage reference generation circuit is programmable and is configured to a generate the input reference voltage based on a programmed reference voltage selection. In this manner, the ACAL circuit can be used to measure the input circuit voltage in an iterative manner based on different programmed input reference voltages for a more precise measurement of the input circuit voltage.