An amplifier circuit includes a primary differential amplifier circuit connected to receive a differential input and provide a primary differential output with a first non-linearity. A secondary differential amplifier circuit is connected to receive the differential input. The secondary differential amplifier circuit is configured to generate a secondary differential output with a second non-linearity. The secondary differential output and the primary differential output are coupled together with opposing polarities such that the second non-linearity cancels out at least the first non-linearity.

A charge-steering amplifier circuit and a control method thereof are provided. The charge-steering amplifier circuit is used for amplifying a differential input signal and includes a sample-and-hold circuit, a charge-steering amplifier, a reference voltage generation circuit, and a switch circuit. The sample-and-hold circuit is configured to sample the differential input signal to generate first and second sampled signals. The charge-steering amplifier has a first input terminal, a second input terminal, a first output terminal, and a second output terminal. The first and second input terminals receive the first and second sampled signals, respectively. The reference voltage generation circuit is configured to generate a reference voltage according to the differential input signal. The switch circuit is configured to couple the reference voltage to the first output terminal and the second output terminal.

A highly linear time amplifier with power supply rejection. In a reset stage, the threshold value of an over-threshold detector is used for resetting an output node of an amplifier, to eliminate the impact of power supply voltage changes on the threshold value of the threshold detector. A node capacitor unit is charged under the control of an input clock signal. After completion of charging, the node capacitor unit is discharged under the control of a synchronous clock signal. The time amplification gain only depends on the proportion of the charge and discharge current, and the charging and discharging time are completely linear in principle, which eliminates the nonlinearity of the traditional time amplifier, and reduces the negative impact of threshold change on system performance.

Circuit techniques for providing base-current cancellation of a bipolar junction transistor (BJT) differential pair that compensate for tail current noise and differential voltage transients without penalizing supply headroom.

In an embodiment, an electronic circuit includes: an input differential pair including first and second transistors; a first pair of transistors in emitter-follower configuration including third and fourth transistors, and an output differential pair including fifth and sixth transistors. The third transistor has a control terminal coupled to the first transistor, and a current path coupled to a first output terminal. The fourth transistor has a control terminal coupled to the second transistor, and a current path coupled to a second output terminal. The fifth transistor has a control terminal coupled to the first transistor, and a first current path terminal coupled to the first output terminal. The sixth transistor has a control terminal coupled to the second transistor, and a first current path terminal coupled to the second output terminal. First and second termination resistors are coupled between the first pair of transistors and the output differential pair.

An electronic device may include wireless circuitry with a processor, a transceiver, an antenna, and a front-end module coupled between the transceiver and the antenna. The front-end module may include one or more radio-frequency amplifiers for amplifying a radio-frequency signal. The radio-frequency amplifier may include input transistors cross-coupled with capacitance neutralization transistors and/or coupled to cascode transistors. One or more n-type gain adjustment transistors may be coupled to source terminals of the capacitance neutralization transistors. One or more p-type gain adjustment transistors may be coupled to source terminals of the cascode transistors. One or more processors in the electronic device can selectively activate one or more of the gain adjustment transistors to reduce the gain of the radio-frequency amplifier without degrading noise performance and without altering the in-band frequency response of the radio-frequency amplifier.

A multi-stage amplifier circuit includes: a front stage amplification circuit, for generating a front stage amplification signal according to a difference between a primary reference signal and a primary feedback signal; an output adjustment circuit, for generating a driving signal according to the front stage amplification signal; and an output transistor, controlled by the driving signal to generate an output signal. The output adjustment circuit includes: an adjustment transistor biased by a differential current of the front stage amplification signal; and an impedance adjustment device biased by the differential current. A resistance of the impedance adjustment device is determined by a difference between an adjustment feedback signal and an adjustment reference signal. The driving signal is determined by a product of a resistance of the impedance adjustment device multiplied by the differential current of the front stage amplification signal, and a drain-source voltage of the adjustment transistor.

A power amplifier circuit including a plurality of analog power amplifiers configured to generate a output power for an output signal; at least one processor configured to: select a highest output power signal; determine an input signal power of a modulated signal; determine an output signal power based on the input signal power; compare the output signal power and the highest output power; and disable a subset of the plurality of analog power amplifiers based on the comparison, wherein a remainder of the plurality of analog power amplifiers are configured to generate the output signal power.

The present invention provides an amplifier circuit, wherein the amplifier circuit includes an input terminal, a capacitor, an amplifier, a feedback circuit and an aliasing tone cancellation circuit. The input terminal is configured to receive a first input signal. The capacitor is coupled to the input terminal. The amplifier is configured to receive the input signal through the capacitor to generate an output signal. The feedback circuit is coupled between an input node and an output node of the amplifier, and is configured to generate a feedback signal according to the output signal, wherein the feedback circuit includes a storage block including a switched-capacitor. The aliasing tone cancellation circuit is coupled between the input terminal of the amplifier circuit and the input node of the amplifier, and configured to generate a signal to cancel or reduce an aliasing tone of the feedback signal according to the input signal.

A circuit includes a main amplifier having a first input and a first output. A main bias circuit is coupled to the main amplifier, and the main bias circuit configured to operate the main amplifier in a first frequency band. A feedforward cancellation amplifier has a second input and a second output, in which the second input is coupled to the first input, and the second output is coupled to the first output. A filter is coupled between the first input and the second input. A feedforward bias circuit is coupled to the feedforward cancellation amplifier. The feedforward bias circuit is configured to operate the feedforward cancellation amplifier in a second frequency band within and narrower than the first frequency band.