A power amplifier circuit includes: a transistor which is supplied at a base with a bias current, amplifies an input signal, and outputs a current; a transistor which is connected at a base to the base of the transistor and in which a current commensurate with the current is input to a collector; a transistor which outputs a bias control signal which controls supply of the bias current; and a control circuit which is connected to the collector of the transistor and a gate of the transistor and controls a bias control signal on the basis of a reference current based on a reference signal and the current.

Devices and methods for operating a charge pump. In some implementations, a charge pump module includes a clock circuit configured generate to a first clock signal and a second clock signal, the first clock signal having a lower frequency than the second clock signal. The charge pump module also includes a driving circuit configured to generate a first set of clock signals based on the first clock signal and a second set of clock signals based on the second clock signal, the driving circuit coupled to the clock circuit. The charge pump module further includes a charge pump core including a set of capacitances, the charge pump core configured to charge the set of capacitances based the first set of clock signals and the second set of clock signals.

An acoustic wave device includes a silicon support substrate that includes first and second main surfaces opposing each other, a piezoelectric structure provided on the first main surface and including the piezoelectric layer, an IDT electrode provided on the piezoelectric layer, a support layer provided on the first main surface of the silicon support substrate and surrounding the piezoelectric layer, a cover layer provided on the support layer, a through-via electrode that extending through the silicon support substrate and the piezoelectric structure, and a first wiring electrode connected to the through-via electrode and electrically connected to the IDT electrode. The piezoelectric structure includes at least one layer having an insulating property, the at least one layer including the piezoelectric layer. The first wiring electrode is provided on the layer having an insulating property in the piezoelectric structure.

A multi-level charge pump (MCP) circuit is provided. The MCP circuit includes a multi-level voltage circuit configured to receive a supply voltage and generate a low-frequency voltage. The multi-level voltage circuit includes a first switch path, a second switch path, and a third switch path each having a respective on-resistance and coupled in parallel between an input node and an output node. In a non-limiting example, the multi-level voltage circuit is configured to activate the first switch path and at least one of the second switch path and the third switch path when the multi-level voltage circuit generates the low-frequency voltage that equals the supply voltage. By activating at least two of the three switch paths to generate the low-frequency voltage, it may be possible to reduce an equivalent resistance of the multi-level voltage circuit, thus helping to improve efficiency and reduce power loss of the MCP circuit.

A wideband envelope modulator comprises a direct current (DC)-to-DC switching converter connected in series with a linear amplitude modulator (LAM). The DC-DC switching converter includes a pulse-width modulator that generates a PWM signal with modulated pulse widths representing a time varying magnitude of an input envelope signal or a pulse-density modulator that generates a PDM signal with a modulated pulse density representing the time varying magnitude of the input envelope signal, a field-effect transistor (FET) driver stage that generates a differential PWM or PDM drive signal, a high-power output switching stage that is driven by the PWM or PDM drive signal, and an output energy storage network including a low-pass filter (LPF) of order greater than two that filters a switching voltage produced at an output switching node of the high-power output switching stage.

Power supplies for electronic devices (e.g. medical imaging devices) are disclosed herein. In one embodiment, a switched mode power supply is minimized in size and weight while maintaining efficiency and an artifact-free image using power supply design techniques tailored to increasing the power conversion frequency to be above the desired receive band of an ultrasound imaging system. In another embodiment, a switched mode power supply is minimized in size and weight while maintaining efficiency and an artifact-free image using power supply design techniques tailored to increasing the power conversion frequency to be just below the desired receive band of an ultrasound imaging system causing the third harmonic and possibly the second harmonic to fall just above the desired receive band.

An envelope tracking (ET) integrated circuit (ETIC) supporting multiple types of power amplifiers. The ETIC includes a pair of tracker circuits configured to generate a pair of low-frequency currents at a pair of output nodes, respectively. The ETIC also includes a pair of ET voltage circuits configured to generate a pair of ET voltages at the output nodes, respectively. In various embodiments disclosed herein, the ETIC can be configured to generate the low-frequency currents independent of what type of power amplifier is coupled to the output nodes. Concurrently, the ETIC can also generate the ET voltages in accordance with the type of power amplifier coupled to the output nodes. As such, it is possible to support multiple types of power amplifiers based on a single ETIC, thus helping to reduce footprint, power consumption, and heat dissipation in an electronic device employing the ETIC and the multiple types of power amplifiers.

A power supply modulator includes: a first switching element in which a first voltage is applied to the first terminal and the second terminal is connected to an output terminal; a second switching element in which the third terminal is connected to the output terminal and the second terminal, and a second voltage is applied to the fourth terminal; a first driver circuit in which the first voltage is applied to the fifth terminal and the sixth terminal is grounded, to control opening and closing of the first switching element by a change in a resistance value between the fifth and sixth terminals; and a second driver circuit in which the seventh terminal is grounded and the second voltage is applied to the eighth terminal, to control opening and closing of the second switching element by a change in a resistance value between the seventh and eighth terminals.

The present disclosure discloses a direct current (DC)-DC boost converter, which includes a battery terminal providing a battery voltage, a charge pump coupled between the battery terminal and an interior node, and a power inductor coupled between the interior node and a power supply terminal that provides a power voltage to a radio frequency transceiver. The charge pump is configured to provide an interior voltage at the interior node based on the battery voltage. Herein, the interior voltage toggles between the battery voltage and two times the battery voltage. The charge pump includes a first switch coupled between the battery terminal and the interior node, a second switch coupled between the battery terminal and a connecting node, a third switch coupled between the connecting node and ground, and a flying capacitor coupled between the interior node and the connecting node of the second switch and the third switch.

A tracking power supply includes a power conversion subsystem and one or more tracking subsystems. The power conversion subsystem is configured to generate N power rails, where N is an integer greater than one. Each tracking subsystem includes a switching network and a controller. The switching network is electrically coupled between each of the N power rails and a tracking power rail of the tracking power supply. The controller is configured to control operation of the switching network according to a tracking signal associated with a load powered by the tracking power supply, such that a voltage at the tracking power rail is one of two or more values, as determined at least partially based on the tracking signal. The controller is further configured to adjust voltage of at least one of the N power rails.