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.

In order to realize a circuit in a subsequent stage with a smaller circuit scale with respect to a single-ended input of a large signal, a double-sampling switched-capacitor input circuit includes a first switched-capacitor input circuit, which includes first capacitors for double sampling, and a second switched-capacitor input circuit, which includes second capacitors for double sampling, and which is configured to operate in opposite phase to the first switched-capacitor input circuit, the double-sampling switched-capacitor input circuit having a configuration in which the first capacitors and the second capacitors have different values, and in which the value of the second capacitors is adjusted so that a signal is attenuated.

Certain aspects of the present disclosure provide amplifiers. Certain aspects of the present disclosure provide methods and apparatus for protecting an such amplifiers, for example an audio amplifier, or a delta-sigma modulator from saturation. One example amplifier generally includes an output stage comprising a plurality of transistors; and a feedback network having an input coupled to an output of the output stage and comprising a plurality of integrators connected in series. At least one of the plurality of integrators generally includes an operational amplifier having an input and an output, a first resistive element coupled to the input of the operational amplifier, a capacitive element coupled between the input and the output of the operational amplifier; and a first switch coupled between the input and the output of the operational amplifier. For certain aspects, the amplifier may be a class-D amplifier or a direct digital feedback amplifier (DDFA).

A Successive Approximation Register Analog-to-Digital Converter (SAR ADC) is disclosed. The SAR ADC includes a switched capacitor array, a buffer, a comparator and a control logic circuit. The switched capacitor array is arranged to sample an input signal according to a switch control signal to generate a sampling signal. The buffer is arranged to generate a common mode voltage. The comparator is arranged to receive the sampling signal and the common mode voltage in order to generate a comparison result. The control logic circuit is arranged to generate an output signal according to the comparison result, and generate the switch control signal to control the switched capacitor array. The control logic circuit further generates an operation control signal to adjust a Miller compensation capacitor inside the buffer. An associated control method is also disclosed.

A preamplifier amplifies signals input to first and second input terminals. A first switching circuit receives first and second input signals and respectively outputs those signals to the first and second input terminals. A switched capacitor circuit samples two signals amplified by the preamplifier. An integration circuit includes a fully differential operational amplifier outputting amplifying differential signals input between third and fourth input terminals between second and first output terminals, and first and second integration capacitors. A second switching circuit switches a connection relationship between the switched capacitor circuit, and the first and second integration capacitors. A third switching circuit switches a connection relationship between the first and second integration capacitors, and third and fourth output terminals. A cycle including sampling and signal integration is performed twice, and the first to third switching circuits switch the connection relationships each time the cycle changes.

A high dynamic range sensing front-end for bio-signal recording systems in accordance with embodiments of the invention are disclosed. In one embodiment, a bio-signal amplifier includes an input signal, where the input signal is modulated to a predetermined chopping frequency, a first amplifier stage, a parallel-RC circuit connected to the first amplifier stage and configured to generate a parallel-RC circuit output by selectively blocking an offset current, a second amplifier stage connected to the parallel-RC circuit that includes a second input configured to receive the parallel-RC circuit output and generate a second output that is an amplified version of the input signal with ripple-rejection. Further, the bio-signal amplifier can also include an auxiliary path configured for boosting input impedance by pre-charging at least one input capacitor. In addition, the bio-signal amplifier can also include a DC-servo feedback loop that includes an integrator that utilizes a duty-cycled resistor.

In a preamplifier (amplifier) for the radiation detector, an interconnection layer connected to the bonding pad forms one electrode of a feedback capacitor. Since there is no wiring for connecting the bonding pad and capacitor, a parasitic capacitance caused by the wiring will not be generated. Moreover, the capacitor is arranged below the bonding pad with a conductive layer serving as the other electrode, so that the feedback capacitance of the capacitor is included in the parasitic capacitance between the interconnection layer and the substrate. Compared to the conventional case, an amount of capacitance corresponding to the parasitic capacitance caused by wiring and the feedback capacitance for the capacitor is reduced from the input capacitance. Thus, the input capacitance for the amplifying circuit is reduced.

An amplifier circuit includes a main amplifier and an auxiliary circuit that improves a slew rate of the main amplifier. The main amplifier is composed of a one-stage CMOS amplifier, amplifies a voltage difference between two input signals, and outputs, from output terminals, an output signal corresponding to the voltage difference of the input signals. The auxiliary circuit controls an auxiliary bias current flowing through the output terminals according to the voltage difference of the input signals, and interrupts the auxiliary bias current at a predetermined timing before completion of settling. Such a scheme enables improvement of a slew rate by the auxiliary circuit and high-speed operation as well as reduction of error due to mismatch between the main amplifier and the auxiliary circuit, thereby yielding high-accuracy output signal output therefrom.

A switched-capacitor amplifier circuit includes multiple switched-capacitor networks, an amplifier, and multiple reset circuits. The switched-capacitor networks are configured to receive respective input voltages during a sampling phase, and generate sampled voltages. During an amplification phase, the amplifier is coupled with the switched-capacitor networks, and is configured to receive the sampled voltages. The amplifier is further configured to generate output voltages. During the sampling phase, the amplifier is coupled with the reset circuits, and is further configured to receive divided voltages such that the amplifier is reset. The reset circuits are configured to receive and provide a common-mode voltage and the output voltages to the amplifier. The divided voltages are generated based on the common-mode voltage and the output voltages. Each reset circuit includes at least one of a resistor and a capacitor.

A switched-capacitor amplifier includes a sampling capacitor, a first switch, a differential amplifier, a reference power supply, a second switch, a third switch, and a controller configured to execute on and off control of the first to third switches. The second switch includes a series circuit of first and second metal oxide semiconductor (MOS) transistors and a potential holding capacitor connected between a node that is a common connection point of the first and second MOS transistors and a ground.