An impedance control unit is disclosed. Also disclosed are a balun unit, an electronic device, and a Doherty amplifier, each comprising the impedance control unit. The impedance control unit comprises a pair of re-entrant type coupled lines, and further comprises an electrical short between the intermediate plane and the ground plane arranged locally inside the pair of coupled lines.

A power amplifier circuit includes a first transistor, wherein a radio frequency signal is inputted to a base or gate of the first transistor; a second transistor having an emitter connected to a collector or drain of the first transistor, wherein a first voltage is supplied to a collector of the second transistor, and a first amplified signal obtained by amplifying the radio frequency signal is outputted from the collector of the second transistor; and a third transistor configured to supply a bias voltage to a base of the second transistor. A second voltage is supplied to a collector or drain of the third transistor, a third voltage corresponding to the first voltage is supplied to a base or gate of the third transistor, and the bias voltage, which corresponds to the third voltage, is supplied from an emitter or source of the third transistor.

A digital power amplifier comprising two or more individually activatable amplifiers. The outputs of the amplifiers are connected causing an activated amplifier of the two or more amplifiers to load modulate another activated amplifier of the two or more amplifiers.

A first system includes first and second buck-boost amplifiers. The first amplifier is connected to a battery, includes a first inductor and a first plurality of switches connected to the first inductor, and drives first and second loads. The second amplifier is connected to the battery, includes a second inductor and a second plurality of switches connected to the second inductor, and drives the first and second loads. A controller drives the first and second plurality of switches to operate each of the first and second amplifiers in a single inductor multiple output mode. A second system includes multiple buck-boost amplifiers connected to a battery and driving respective loads. Each amplifier includes inductors and switches connected to the inductors. A controller drives the switches to utilize one or more inductors based on an amount of power used by each amplifier to drive the respective loads.

This invention relates to switching amplifiers and switching power converters with bipolar outputs. A new circuit configuration is disclosed which is neither single ended nor bridged. This introduces a new category of amplifiers and power converters, which are spanning. Also disclosed are new circuit topologies and new switching sequence strategies for such amplifiers and converters. These unlock improvements in power efficiency, space efficiency and cost efficiency. The improvements can be obtained across a wide range of signal amplitudes, with load circuits which may be resistive, partly reactive, or wholly reactive.

An integrated circuit for measuring current while receiving wireless power is described. The integrated circuit measures a current across a resistor by an amplifier. A gain of the amplifier is based on a pair of matched upstairs resistors and a pair of matched downstairs resistors. The pair of matched upstairs resistors may include an offset in resistance. The integrated circuit includes a switch matrix with switches coupled between the integrated resistor and the pair of matched upstairs resistors. The offset for the pair of matched upstairs resistors may be measured by selectively controlling the switches.

Methods and systems for power amplification with digital quantized power supply with multiple amplifiers are disclosed herein. In one embodiment, In one embodiment, a time-varying envelope signal is sampled, quantized and decomposed into several constituent signals that are individually amplified, and then combined to form a desired amplified version of the quantized time-varying envelope. Amplitude, phase and/or frequency characteristics of one or more of the signals and supply voltages V.sub.dd and source current of one or more amplifiers are digital controlled based on the information provided by quantization process and slow and fast power control information. Amplitude, phase and/or frequency characteristics of one or more of the constituent signals to be amplified are controlled to provide the desired amplitude, phase, frequency, and/or spectral characteristics of the desired quantized version of the time-varying envelope signal.

Embodiments of the present invention provide a power amplifier, a radio remote unit RRU, and a base station. A multiphase pulse width modulator performs modulation to generate N multiphase pulse-width modulation PWM signals. The multiphase pulse-width modulation PWMn signal may be amplified. The multiphase pulse-width modulation PWMn signal may be filtered and a combination may be performed at a drain or a collector of a power amplifier transistor. According to the new radio frequency amplifier in accordance with the disclosure, envelope feeding loop inductance can be effectively reduced, so that video bandwidth is increased and DPD correction performance is improved.

A bias circuit includes a current source to generate a reference current, a temperature compensation portion in an off-state in an initial start period in response to a first control signal, and in an on-state in a normal driving period, subsequent to the initial start period, and to receive a first current of the reference current, and a bias output portion to generate a warm up current based on the reference current in the initial start period and to generate a bias current based on a second current, which is lower than the reference current by an amount of the first current, in the normal driving period.

In a Class-D amplifier, first/second ratios and first/second RC time constants are sequentially matched by trimming. An integrator is coupled to differential first/second paths. The first/second ratios are of a feedback resistor to an input resistor in the first/second paths. R's of the first/second RC time constants are the resistors of the first/second matched ratios. C's of the first/second RC time constants are integrating capacitors in the first/second path. For each of multiple power rails, a ramp amplitude is determined based on a sensed voltage. Concurrently, the driver stage is switched from first to second power rails and quantizer switched from first to second ramp amplitudes to achieve constant combined quantizer/driver stage gain. Based on a sensed load current, an IR drop is determined for a respective output impedance of the driver stage and added to a loop filter output to compensate for the respective output impedance.