An A/D converter includes an A/D conversion circuit for converting an analog output signal into a digital signal, and a control circuit for controlling the A/D conversion circuit. The control circuit acquires a digital signal of a first bit indicating which level regions the voltage level of the analog output signal corresponds to in accordance with a first conversion operation by the A/D conversion circuit, sets a reference voltage corresponding to the level region based on the first bit, amplifies the difference voltage between the analog output signal and the reference voltage to correspond to the A/D conversion input range of the A/D conversion circuit, outputs an amplified analog signal, acquires a digital signal of a second bit indicating the voltage level of the amplified analog signal in accordance with a second conversion operation by the A/D conversion circuit, and synthesizes the first bit and the second bit.

An arithmetic logic unit (ALU) includes a front end latch stage coupled to a signal latch stage coupled to a Gray code (GC) to binary stage. First inputs of an adder stage are coupled to receive outputs of the GC to binary stage. Outputs of the adder stage are generated in response to the first inputs and second inputs of the adder stage. A pre-latch stage is coupled to latch outputs of the adder stage. A feedback latch stage is coupled to latch outputs of the pre-latch stage. The second inputs of the adder stage are coupled to receive outputs of the feedback latch stage. The feedback stage includes first conversion gain feedback latches configured to latch outputs of the pre-latch stage having a first conversion gain and second conversion gain feedback latches configured to latch outputs of the pre-latch stage having a second conversion gain.

A sigma-delta ADC comprising: a first-input-resistor connected in series between a first-input-terminal and a first-feedback-node; a second-input-resistor connected in series between a second-input-terminal and a second-feedback-node; a third-input-resistor connected in series between a third-input-terminal and a third-feedback-node; a first-multiplexer-switch connected in series between the first-feedback-node and a first-amplifier-second-input-terminal; a second-multiplexer-switch connected in series between the second-feedback-node and a first-amplifier-first-input-terminal; a third-multiplexer-switch connected in series between the third-feedback-node and the first-amplifier-second-input-terminal; a first-feedback-current-source having a first terminal and second terminal, wherein the second terminal is connected to a reference-terminal; a second-feedback-current-source having a first terminal and second terminal, wherein the second terminal is connected to the reference-terminal; a first-feedback-selection-switch connected in series between the first-feedback-node and the first terminal of the first-feedback-current-source; a second-feedback-selection-switch connected in series between the second-feedback-node and the first terminal of the second-feedback-current-source; and a third-feedback-selection-switch connected in series between the third-feedback-node and the first terminal of the first-feedback-current-source.

According to one embodiment, a semiconductor device includes the following configuration. A detection circuit detects a state of a clock signal. An amplification circuit changes a gain based on the state of the clock signal detected by the detection circuit. An amplification circuit amplifies a first voltage with the gain and outputs a second voltage obtained as a result of amplification. A conversion circuit converts the second voltage output from the amplification circuit to first data. An isolation circuit includes a driver and a receiver electrically isolated from the driver. The driver transmits a signal corresponding to the first data to the receiver. The receiver outputs second data corresponding to the signal transmitted from the driver. The output circuit outputs the second data output from the isolation circuit.

An amplifier performs analog amplification on a signal I_A with a gain corresponding to a state GS and outputs the amplified signal as a signal M_A. An ADC converts the signal M_A to a digital signal and outputs the digital signal as a signal M_D. Analog comparators and a down-determination unit detect that the signal M_A exceeds a first level, and cause the state GS to transition to a state of gain of the next lower stage. Digital comparators and an up-determination unit detect that the signal M_D has been continuously lower than a second level for a predetermined period, and cause the state GS to transition to a state of gain of the next higher stage. The restoration circuit performs digital amplification on the signal M_D with a gain corresponding to the gain of the amplifier and outputs the amplified signal as a signal O_D.

Disclosed are a readout circuit, a signal quantizing method, a signal quantizing device, and a computer device. The readout circuit includes: a signal sampler, including a plurality of channels; a plurality of integrators, connected to the plurality of channels and having a one-to-one relationship with the plurality of channels; a signal processor, including a first operational amplifier, a sampling input of the first operational amplifier being connected to outputs of the plurality of integrators, respectively; and an analog-digital converter. An input of the analog-digital converter is connected to an output of the first operational amplifier.

Apparatus, including a multiplexer, having a first output and multiple first inputs receiving analog input signals and an analog feedback signal and cycling through and selecting the signals for transfer in sequential signal groupings to the first output. The apparatus also includes an amplification circuit, having a second output and a second input connected to the multiplexer first output, that amplifies signals corresponding to the analog input signals with a selected gain so as to generate respective amplified analog signals at the second output. Circuitry selects a characteristic of the respective amplified analog signals from an initial signal grouping, feeds the characteristic back for input to the multiplexer as the analog feedback signal, selects a subsequent characteristic of the respective amplified analog signals from a subsequent signal grouping, and adjusts the amplification circuit gain so that the analog feedback signal and the subsequent characteristic have the same amplitude.

A reference voltage sub-system that allows fast power up after spending extended periods in an ultra-low power standby mode. The reference voltage sub-system includes a reference voltage buffer, a reference voltage keeper, an active calibration facility for selectively adjusting the reference voltage keeper output to match the reference voltage buffer output, and a selection means for selecting between the reference voltage buffer output and the reference voltage keeper output.

An apparatus may include a circuit configured to generate, by an analog to digital converter (ADC), one or more ADC samples based on an input signal. The circuit may be further configured to generate a first estimated signal using a first channel pulse response estimation with a gain constraint based on the one or more ADC samples and generate a second estimated signal using a second channel pulse response estimation with a phase constraint based on the one or more ADC samples.

A reference voltage sub-system that allows fast power up after spending extended periods in an ultra-low power standby mode. The reference voltage sub-system includes a reference voltage buffer, a reference voltage keeper, an active calibration facility for selectively adjusting the reference voltage keeper output to match the reference voltage buffer output, and a selection means for selecting between the reference voltage buffer output and the reference voltage keeper output.