A thermally-isolated-metal-oxide-semiconducting (TMOS) sensor has inputs coupled to first and second nodes to receive first and second bias currents, and an output coupled to a third node. A tail has a first conduction terminal coupled to the third node and a second conduction terminal coupled to a reference voltage. A control circuit applies a control signal to a control terminal of the tail transistor based upon voltages at the first and second nodes so that a common mode voltage at the first and second nodes is equal to a reference common mode voltage. A differential current integrator has a first input terminal coupled to the second node and a second input terminal coupled to the first node, and provides an output voltage indicative of an integral of a difference between a first output current at the first input terminal and a second output current at the second input terminal.

A circuit may include or may be coupled to a precharge structure to reduce or minimize a net perturbation, caused by switching, in the input source. Apparatus and techniques shown herein may enable low input current operation in a signal chain of an analog circuit by such reduction or minimization of such perturbation.

A sample-and-hold amplifier can include: an operational amplifier; a sampling capacitor having a first terminal coupled to an inverting input terminal of the operational amplifier, and a second terminal coupled to a reference ground; and a switching circuit configured to switch feedback paths of the sample-and-hold amplifier in a first stage and a second stage, such that an offset voltage of the operational amplifier is at least partially eliminated.

The disclosure provides a circuit. The circuit includes a gain stage block. The gain stage block is coupled to an input voltage through a first switch. A first capacitor is coupled between the first switch and a ground terminal. A second capacitor is coupled between the first switch and a second switch. A third switch is coupled between the second capacitor and a fixed terminal of the gain stage block.

An amplifier circuit includes a first input branch circuit including a first sampling capacitor, a second input branch circuit including a second sampling capacitor, an averaging capacitor, and a subtraction capacitor, a feedback capacitor, and an operational amplifier. The first sampling capacitor samples an input voltage in a first time period and outputs a first voltage. The second sampling capacitor samples the input voltage in the first time period and outputs a second voltage. The averaging capacitor takes an average of the second voltage in the second time period and outputs a third voltage. The subtraction capacitor receives the third voltage in the first time period. The subtraction capacitor subtracts the first voltage from the third voltage and outputs a fourth voltage in the second time period. The operational amplifier is connected to the feedback capacitor and amplifies the fourth voltage. The first and second time periods are repeated alternately.

An integrated circuit includes an amplifier configured to amplify an analog signal, and an offset adjustment circuit that is provided in a stage prior to the amplifier and that is configured to adjust an offset amount of the analog signal to be amplified by the amplifier.

An amplifying circuit includes a reference voltage generating circuit, a common-mode voltage conversion circuit, a common-mode negative feedback circuit, and an amplifying sub-circuit. The reference voltage generating circuit generates a first reference voltage, a second reference voltage, and a reference common-mode voltage according to a post-stage common-mode voltage. The common-mode voltage conversion circuit converts the pre-stage output differential signal into a differential input signal according to the reference common-mode voltage. The common-mode negative feedback circuit generates a control voltage to quickly establish a common-mode negative feedback of the amplifying sub-circuit, wherein the first reference voltage and the second reference voltage are used to cancel a baseline signal of the pre-stage output differential signal. The amplifying circuit can eliminate the baseline signal, convert the common-mode voltage and quickly establish the common-mode negative feedback.

A detecting device includes a pyroelectric element that generates charge by a pyroelectric effect in a first detection terminal and a second detection terminal, a chopper amplifier circuit that generates an amplified signal in response to the charge generated in the first detection terminal and the second detection terminal by chopping, and an initialization switch that controls electrical connection between the second detection terminal and a power source for generating an initialized voltage, and the initialization switch is turned on before a start of an amplification operation by the amplifier circuit and is off during the amplification operation.

Herein disclosed are multiple embodiments of a signal-processing circuit that may be utilized in various circuits, including conversion circuitry. The signal-processing circuit may receive an input and produce charges on multiple different capacitors during different phases of operation based on the input. The charges stored on two or more of the multiple different capacitors may be utilized for producing an output of the signal-processing circuit, such as by combing the charges stored on two or more of the multiple different capacitors. Utilizing the charges on the multiple different capacitors may provide for a high level of accuracy and robustness to variations of environmental factors, and/or a low noise level and power consumption when producing the output.

A programmable amplifier circuit includes an amplifier, an input capacitor coupled to an input of the amplifier, a feedback capacitor coupled to the input of the amplifier and an output of the amplifier, and a switched-capacitor resistor circuit. The switched-capacitor resistor circuit is coupled between the input of the amplifier and the output of the amplifier, and configured for simulating a feedback resistor element to provide a resistance for a feedback path of the amplifier by using at least one capacitor placed between the input of the amplifier and the output of the amplifier to avoid leakage current(s) flowing back to an input of the amplifier.