The present invention is a system and method for providing a charge detector that utilizes small feedback capacitors in a low-noise, high-gain, system that combines a differential topology in a solid-state amplifier implemented in a complementary metal-oxide semiconductor (CMOS) process with active reset, thereby achieving high dynamic range and robust operations. A custom optoelectronic system is used to measure gain, and while operating at a sampling frequency of 10 kHz, the active reset extends the dynamic range of the charge detector.

A circuit for startup of a multi-stage amplifier circuit includes a pair of input nodes and at least two output nodes configured to be coupled to a multi-stage amplifier circuit. A startup differential stage includes a differential pair of transistors having respective control terminals coupled to the pair of input nodes, and each transistor in the differential pair of transistors has a respective current path therethrough between a respective output node and a common source terminal. The startup differential stage is configured to sense a common mode voltage drop at a first differential stage of the multi-stage amplifier circuit. Current mirror circuitry includes a plurality of transistors coupled to the common terminal of the differential pair of transistors and coupled to two output nodes of the at least two output nodes.

An amplifier circuit includes a first transistor including a signal input portion into which a signal is input from the outside, and a load inductor connected between the first transistor and a power supply line. In addition, the amplifier circuit includes a feedback circuit, which is connected between any position between the load inductor and the first transistor and the signal input portion of the first transistor. The gain and linearity are determined as appropriate in accordance with the amount of feedback from this feedback circuit.

An operational amplifier includes a differential amplification circuit configured to receive and amplify an input voltage to generate an output voltage, and receive a feedback signal, and the feedback signal adjusts a common-mode voltage of the output voltage, a reference voltage generation circuit configured to detect status information of the operational amplifier, and generate a reference voltage based on the status information, where the status information includes a temperature or an operating voltage of the operational amplifier, and a common-mode feedback circuit configured to receive the output voltage and the reference voltage, and provide the feedback signal to the differential amplification circuit based on the output voltage and the reference voltage.

The present invention provides a circuit including a reference voltage generator and a plurality of receivers, wherein the reference voltage generator is configured to generate a reference voltage, and each of the receivers is configured to receive the reference voltage and a corresponding input signal to generate a corresponding output signal. In addition, for at least a specific receiver of the plurality of receivers, the specific receiver comprises at least one amplifying stage, the amplifying stage comprises a first input terminal configured to receive the corresponding input signal, a second input terminal configured to receive the reference voltage, a first output terminal configured to generate a first signal, and a second output terminal configured to generate a second signal; and the specific receiver further comprises a first feedback circuit coupled between the first output terminal and the second input terminal.

A buffer circuit configured to receive first and second input signals through first and second input transistors coupled to a first power voltage node, output a first output signal through a first output node and a second output signal through a second output node based on the first and second input signals. A load circuit is coupled among the first output node, the second output node, and a second power voltage node and a resistance value is adjusted based on at least one of the first and second output signals.

A buffer circuit configured to receive first and second input signals through first and second input transistors coupled to a first power voltage node, output a first output signal through a first output node and a second output signal through a second output node based on the first and second input signals. A load circuit is coupled among the first output node, the second output node, and a second power voltage node and a resistance value is adjusted based on at least one of the first and second output signals.

An apparatus includes a load pair including a first transistor and a second transistor, a common mode feedback circuit comprising a first common mode feedback transistor and a second common mode feedback transistor, wherein a drain of the first common mode feedback transistor is coupled to a source of the first transistor, and a gate of the first common mode feedback transistor is coupled to a drain of the first transistor, and a drain of the second common mode feedback transistor is coupled to a source of the second transistor, and a gate of the second common mode feedback transistor is coupled to a drain of the second transistor, and an offset cancellation stage coupled to outputs of the load pair.

The present disclosure relates to circuitry comprising audio amplifier circuitry for receiving an audio signal to be amplified; and first and second output nodes for outputting first and second differential output signals. The circuitry further comprises common mode buffer circuitry configured to receive a common mode voltage and to selectively output the common mode voltage to the first and second output nodes.

In described examples, an amplifier can be arranged to generate a first stage output signal in response to an input signal. The input signal can be coupled to control a first current coupled from a first current source through a common node to generate the first stage output signal. A replica circuit can be arranged to generate a replica load signal in response to the input signal and in response to current received from the common node. A current switch can be arranged to selectively couple a second current from a second current source to the common node in response to the replica load signal.