According to one embodiment, a transformer-based in-phase and quadrature (IQ) includes a differential balun having a first inductor and a second inductor. The first inductor has a first input terminal and a first output terminal. The second inductor has a second input terminal and a second output terminal. Additionally, the IQ generator circuit includes a third inductor magnetically coupled with the first inductor. The third inductor has a first isolation terminal and a third output terminal. The IQ generator circuit also includes a fourth inductor magnetically coupled with the second inductor. The fourth inductor has a second isolation terminal and a fourth output terminal. The IQ generator circuit additionally includes a first transistor coupled to the first input terminal of the first inductor. Further, the generator circuit includes a second transistor coupled to the second input terminal of the second inductor. The first transistor, the second transistor, the first inductor, and the second inductor form a part of a differential amplifier.

The present invention is directed to electrical circuits and techniques thereof. More specifically, an embodiment of the present invention provides a variable gain amplifier that includes a first transistor and a second transistor whose gate terminals are coupled to a first input terminal. A first drain terminal of the first transistor and a first source terminal of the second transistor is coupled to a voltage gain control switch. There are other embodiments as well.

The disclosure relates to a driver amplifier circuit. The driver amplifier circuit includes a non-linear differential amplifier and a non-linear resistor connected across output terminals of the differential amplifier. The non-linear resistor has a resistance value that increases as the differential voltage amplitude across the non-linear resistor increases. A transmitter may include the driver amplifier.

According to one embodiment, a transformer-based in-phase and quadrature (IQ) includes a differential balun having a first inductor and a second inductor. The first inductor has a first input terminal and a first output terminal. The second inductor has a second input terminal and a second output terminal. Additionally, the IQ generator circuit includes a third inductor magnetically coupled with the first inductor. The third inductor has a first isolation terminal and a third output terminal. The IQ generator circuit also includes a fourth inductor magnetically coupled with the second inductor. The fourth inductor has a second isolation terminal and a fourth output terminal. The IQ generator circuit additionally includes a first transistor coupled to the first input terminal of the first inductor. Further, the generator circuit includes a second transistor coupled to the second input terminal of the second inductor. The first transistor, the second transistor, the first inductor, and the second inductor form a part of a differential amplifier.

A power amplifier provides reduction of click and pop in audio applications. The power amplifier includes a first amplifier and an auxiliary amplifier. The auxiliary amplifier is used to ramp the power amplifier output from ground to an offset voltage to reduce the “click and pop” sound. The first amplifier and the auxiliary amplifier having a shared feedback loop. An output of the first amplifier and an output of the auxiliary amplifier may be switchably coupled to the shared feedback loop. A wave generator controls a switch to couple the first amplifier output or the auxiliary amplifier output to the shared feedback loop.

A power amplifier provides reduction of click and pop in audio applications. The power amplifier includes a first amplifier and an auxiliary amplifier. The auxiliary amplifier is used to ramp the power amplifier output from ground to an offset voltage to reduce the “click and pop” sound. The first amplifier and the auxiliary amplifier having a shared feedback loop. An output of the first amplifier and an output of the auxiliary amplifier may be switchably coupled to the shared feedback loop. A wave generator controls a switch to couple the first amplifier output or the auxiliary amplifier output to the shared feedback loop.

In one general aspect, an amplifier can include an input amplifier circuit configured to receive a bias current and receive, as an input, a signal pair connected differentially to the input amplifier circuit, the input amplifier circuit configured to output a differential output signal pair based on the received differential input signal pair, a feedback amplifier circuit configured to receive an average of the differential output signal pair and configured to provide a bias setting output for controlling the bias current, and an output buffer circuit configured to buffer the differential output signal pair, the buffering resulting in a buffered differential output signal pair capable of driving a resistive load.

There is provided a polyphase filter (5) that generates first differential signals from first signals amplified by a first transistor (2-1), outputs the first differential signals from a first output terminal (5-1) and a third output terminal (5-3), generates second differential signals from second signals amplified by a second transistor (2-2), and outputs the second differential signals from the first output terminal (5-1) and the third output terminal (5-3).

A power amplifier includes a two-dimensional matrix of NM active cells formed by stacking main terminals of multiple active cells in series. The stacks are coupled in parallel to form the two-dimensional matrix. The power amplifier includes a driver structure to coordinate the driving of the active cells so that the effective output power of the two-dimensional matrix is approximately NM the output power of each of the active cells.

A power amplifier includes a two-dimensional matrix of NM active cells formed by stacking main terminals of multiple active cells in series. The stacks are coupled in parallel to form the two-dimensional matrix. The power amplifier includes a driver structure to coordinate the driving of the active cells so that the effective output power of the two-dimensional matrix is approximately NM the output power of each of the active cells.