Mechanisms for reducing or eliminating a quantization error caused by a quantizer of a continuous-time (CT) residue generation system are disclosed. In particular, systems and methods described herein are based on using a dither generation and injection circuit that can perform a high-pass filtering of the additive dither signal (i.e., a high-pass shaped dither signal). Using high-pass shaped dither signals is expected to improve quantizer linearity without significantly reducing the available error correction range. The applied dither may be particularly effective at minimizing signal-dependent distortion in ADC output spectrum caused by the quantizer when the quantization error cancellation accuracy may be insufficient.

An analog-to-digital converter includes a first converter stage, a second converter stage coupled to the first converter stage to quantize a residue signal of the first converter stage, and an inter-stage converter disposed between the first and second converter stages. The inter-stage converter is configured to convert between a first domain and a second domain. The inter-stage converter is configured to process the residue signal of the first converter stage such that a range of the residue signal matches a full scale of the second converter stage.

A system may include ADC circuitry. To test the performance of the ADC circuitry, the system may include ADC testing circuitry coupled to the ADC circuitry. In particular, the ADC testing circuitry may include reference voltage generation circuitry configured to generate reference voltages serving as test voltages for the ADC circuitry. The ADC circuitry may be coupled to a test input for receiving the test voltages via switching circuitry and may be coupled to a main data input for receiving system data via the switching circuitry. Testing may occur during an idling time period of the system and when the switching circuitry couples the test input to the ADC circuitry. Test input voltages corresponding to one or more stages in the ADC circuitry may be provided to the ADC circuitry, and corresponding output values from the ADC circuitry may be compared to an expected value and/or expected threshold values.

Systems with object detection capabilities may include a radio detection and ranging (RADAR) system. The RADAR system or other portions of the systems may include analog-to-digital converter circuitry. The analog-to-digital converter circuitry may be implemented as pipeline analog-to-digital converter circuitry having multiple stages. Each stage may include multiplying digital-to-analog converter circuitry having a sampling network and amplifier circuitry. The amplifier circuitry may be implemented as a two-stage amplifier. One or more transistors in the two-stage amplifier may receive adaptive control signals that counteract bias current changes across the one or more transistors due to supply voltage changes.

A pipelined successive approximation register analog-to-digital converter (2), SAR ADC, comprises a first SAR ADC stage (4); an inter-stage amplifier (6) for amplifying an analog residue from the first SAR ADC stage; and a second SAR ADC stage (8) input from the inter-stage amplifier, wherein the inter-stage amplifier (6) comprises one or more MOS transistors (16, 18), wherein the source and drain terminals of each of the one or more MOS transistors (16, 18) are connected to each other and may be toggled between ground and a supply voltage.

An analog-to-digital converter (“ADC”) includes an input terminal configured to receive an analog input voltage signal. A first ADC stage is coupled to the input terminal and is configured to output a first digital value corresponding to the analog input voltage signal and a first analog residue signal corresponding to a difference between the first digital value and the analog input signal. An inverter based residue amplifier is configured to receive the first analog residue signal, amplify the first analog residue signal, and output an amplified residue signal. The amplified residue signal is converted to a second digital value, and the first and second digital values are combined to create a digital output signal corresponding to the analog input voltage signal.

An analog-to-digital converter includes: a voltage-current converter receiving an analog input voltage, generating a first digital signal from the analog input voltage, and outputting a residual current remaining after the first digital signal; a current-time converter converting the residual current into a current time in a time domain; and a time-digital converter receiving the residual time, and generating a second digital signal from the residual time, wherein the first digital signal and the second digital signal are sequences of digital codes representing respective signal levels of the analog input voltage.

An analog-to-digital converter (“ADC”) includes an input terminal configured to receive an analog input signal. A first ADC circuit is coupled to the input terminal and includes a VCO. The first ADC circuit is configured to output a first digital signal in a frequency domain based on the analog input signal. The first digital signal includes an error component. A first DAC is configured to convert the first digital signal to an analog output signal. A first summation circuit is configured to receive the analog output signal, the analog input signal, and a loop filtered version of the analog input signal and extract the error component, and output a negative of the error component. A second ADC circuit is configured to convert the negative of the error component to a digital error signal. A second summation circuit is configured to receive the first digital signal and the digital error signal, and to output a digital output signal corresponding to the analog input at an output terminal.

An analog-to-digital conversion circuit (100) is disclosed. It comprises a switched-capacitor SAR-ADC, (110) arranged to receive an analog input signal (x(t)) and a clock signal, to sample the analog input signal (x(t)), and to generate a sequence (W(n)) of digital output words corresponding to samples of the analog input signal (x(t)), wherein the SAR-ADC (110) is arranged to generate a bit of the digital output word per cycle of the clock signal. It further comprises a clock-signal generator (120) arranged to supply the clock signal to the SAR-ADC (110), and a post-processing unit (140) adapted to receive the sequence (W(n)) of digital output words and generate a sequence of digital output numbers (y(n)), corresponding to the digital output words, based on bit weights assigned to the bits of the digital output words. The bit weights are selected to compensate for a decay of a signal internally in the SAR-ADC (110).

The techniques of this disclosure can cancel or reduce the kT/C noise directly before the gain stage. The effect of the kT/C noise can be greatly reduced, allowing both lower noise conversion and smaller sampling capacitors, which can reduce the die area and reduce the power consumption of the ADC.