An image sensor and electronic apparatus comprise a pixel circuit configured to generate an analog signal; a vertical signal line configured to convey the analog signal from the pixel circuit; an analog amplifier circuit configured to receive the analog signal via the vertical signal line and generate an amplified signal; and a tail current boost circuit configured to modify an instantaneous gain bandwidth product of the analog amplifier circuit by temporarily modifying a tail current of the analog amplifier circuit.

A receiving circuit may include a first amplifying circuit, a second amplifying circuit, a third amplifying circuit, and a feedback circuit. The first amplifying circuit amplifies a first input signal and a second input signal to generate a first amplified signal and a second amplified signal, respectively. The second amplifying circuit amplifies the first amplified signal and the second amplified signal to generate a first preliminary output signal and a second preliminary output signal, respectively. The third amplifying circuit amplifies the first preliminary output signal and the second preliminary output signal to generate a first output signal and a second output signal, respectively. The feedback circuit changes voltage levels of the first amplified signal and the second amplified signal based on a current control signal, the first output signal, and the second output signal.

Low-load-modulation, broadband power amplifiers and method of use are described. The amplifiers can include multiple amplifiers connected in parallel to amplify a signal that has been divided into parallel circuit branches. One of the amplifiers can operate as a main amplifier in a first amplification class and the remaining amplifiers can operate as peaking amplifiers in a second amplification class. The main amplifier can see low modulation of its load between the fully-on and fully backed-off states of the amplifier. With lower load modulation, the power amplifiers described herein exhibit better power-handling capability and RF fractional bandwidth as compared to conventional amplifiers.

Various embodiments relate to an amplifier circuit including: a first transistor having a first and second current conducting terminals and a control terminal; a second transistor having a first and second current conducting terminals and a control terminal, in which the second current-conducting terminal of the first transistor is connected to the first current-conducting terminal of the second transistor; a first inductor with a first terminal coupled to a first current-conducting terminal of the first transistor and a second terminal coupled to an output of the amplifier circuit; a feedback circuit connected between the output and the control terminal of the second transistor, wherein the feedback circuit includes a first resistor, a second inductor, and a first capacitor; and an input of the amplifier circuit connected between the first resistor and the second inductor, wherein a second current-conducting terminal of the second transistor is connected to a first ground terminal, and wherein a control terminal of the first transistor is connected to a second ground terminal via a third capacitor.

An apparatus and method for using the known phenomena of quantum gate tunneling in semiconductor transistors to define the DC state of a charge-coupled amplifier is described. A first stage in which the tunneling current is bipolar (by pairing PMOS and NMOS transistors) in combination with a second stage with a controlled common mode voltage that can be used to control the first stage tunneling current, and thus the common mode voltage at the input. This can be done without the use of additional elements that may degrade performance or power consumption, since the input devices both process the input signal and maintain the DC operating point of the circuit. The approach may be advantageously used not only in charge-coupled amplifiers as described herein, but also in other capacitively coupled circuits such as charge balancing analog to digital converters (ADCs) and digital to analog converters (DACs).

A transimpedance amplifier circuit for generating an output voltage in accordance with an input current includes an offset resistor, a common emitter inverting amplifier having a first input and a first output, the first input receiving the input current, an emitter follower having a second input and a second output, the second input being coupled to the first output through the offset resistor, the second output outputting the output voltage, a feedback resistor connected between the second output and the first input, a variable current source connected to a node between the offset resistor and the second input, the variable current source configured to provide an offset current to the offset resistor, the offset current having a current value varied in accordance with a control signal, and a control circuit configured to generate the control signal so that an average voltage of the first output approaches a preset voltage value.

A bi-directional amplifier (BDA) comprises a first pair of amplifier transistors and a second pair of amplifier transistors, wherein the first pair of amplifier transistors are cross-coupled with the second pair of amplifier transistors, and wherein the first pair of amplifier transistors and the second pair of amplifier transistors each comprise a differential common-emitter (CE) pair (or common-source (CS) pair) with equal transistor size or different transistor size. The BDA further comprises a plurality of blocking capacitors to decouple the collector and the base biases of the first pair of amplifier transistors and the second pair of amplifier transistors. Alternatively or additionally, the BDA further comprises two input/output baluns, through which a common voltage bias is applied to the collectors of each of the differential CE pairs (or drains of CS pairs in some implementations). The baluns enable single-ended measurement and characterization.

An operational amplifier includes a first amplifying unit, a second amplifying unit, a current source, a first compensation capacitor, and a second compensation capacitor. The first amplifying unit includes a first input transistor, a second input transistor, a third input transistor, and a fourth input transistor. The second amplifying unit includes a fifth input transistor, a sixth input transistor, a seventh input transistor, and an eighth input transistor. One end of the first compensation capacitor is coupled to a drain of the seventh input transistor, and the other end of the first compensation capacitor is coupled to a gate of the eighth input transistor. One end of the second compensation capacitor is coupled to a drain of the eighth input transistor, and the other end of the second compensation capacitor is coupled to a gate of the seventh input transistor.

A linear amplifier outputs differential signals corresponding to differential signals input to a first signal input terminal and a second signal input terminal, and includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor, a third transistor, a fourth transistor, a differential amplifier, and a signal processing circuit. The signal processing circuit includes a first transistor and a second transistor, and includes a resistor as a common voltage output part that outputs a common voltage. The differential amplifier receives the common voltage and a reference voltage, and applies a voltage corresponding to the voltage difference between the common voltage and the reference voltage to the control terminals of the transistors.

The present disclosure provides a radio frequency (RF) front-end of a low power consumption and fully automatic adjustable broadband receiver, including a low-noise amplification module, amplifying an broadband single-ended RF signal, and converting it into differential current signal; a local oscillator, generating a local oscillator signal; an quadrature mixer, quadraturely mixing the differential current signal and the local oscillator signal to generate intermediate frequency differential current signals; a transimpedance amplifier, converting the intermediate frequency differential current signal into an intermediate frequency differential voltage signal; an IIP2 calibration module, reducing the IIP2 effect of the RF front end; a received signal strength indicator module, sending the first amplification factor control signal and the differential mismatch control signal to the low noise amplification module, and sending the second amplification factor control signal to the transimpedance amplifier, thereby making the intermediate frequency differential voltage signals meet the requirements of the amplitude and mismatch.