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.

The present invention, a Digital Power Amplifier (DPA) with filtered output relates to the transmission circuitry of wireless communications systems and more particularly to high frequency power amplifier circuits using digital intensive techniques on cost efficient semiconductor technologies. Today, we experience an ever-increasing need for low cost, low power wireless transmitters in the millimeter wavelength region. Current solutions rely on analog PA circuits. The background art does not contain a solution for bridging the gap between the operation frequencies of the digital circuits on a cost-efficient technology such as CMOS and the millimeter wavelength transmission frequencies demanded in numerous applications. The DPA allowing the direct feeding of digital data to a high frequency amplifying circuit. In this way, design challenging and costly analog processing up-conversion stages are avoided. The DPA comprises a bank of switching amplifying elements, a switch capacitor trap filter taping on the bank of switching amplifying elements for shaping the frequency characteristic of the produced radio frequency (RF) waveform and an adaptive biasing circuit able of dynamically controlling the power consumption within the switching amplifying elements. It can have a wide spectrum of applications where low cost but high efficiency power amplifiers are needed, such as in the Internet of Things (IoT), Wi-Fi and 5G cellular communications.

An embodiment pulse-width modulation (PWM) modulator circuit comprises a first half-bridge stage having a first output node and a second half-bridge stage having a second output node. The first output node and the second output node are configured to have an electrical load coupled therebetween to apply thereto a PWM-modulated output signal. The circuit comprises a differential stage having input nodes configured to receive an input signal applied between the input nodes and produce a differential control signal for the first half-bridge stage and the second half-bridge stage. A current comparator is arranged intermediate the differential stage and the first and second half-bridge stages. The current comparator is configured to produce a PWM-modulated drive signal to drive the half-bridge stages as a function of the input signal applied between the input nodes in the differential stage.

Described are concepts, systems, circuits and techniques directed toward methods and apparatus for generating one or more pulse width modulated (PWM) waveforms with the ability to dynamically control pulse width and phase with respect to a reference signal.

A digital power amplifier for a signal, the digital power amplifier comprising: a first activatable amplifier; a second activatable amplifier; and an output network, wherein an output of the first amplifier and an output of the second amplifier are coupled to the output network, and wherein the amplifiers and/or the output network are configured such that four output levels are obtainable at an output of the output network, and said output levels are configured to optimise a linearity of the digital power amplifier for said signal.

Class-D amplifier circuits provide operation with low-distortion zero crossings outside of a unipolar power supply voltage range. The amplifiers include a first H-bridge driver circuit and a second H-bridge driver circuit. The class-D amplifier circuits also include a control circuit having an input for receiving an input signal to be reproduced by the class-D amplifier circuit. The control circuit has outputs coupled to inputs of the first and second H-bridge drivers, and includes one or more modulators. The control circuit selects between actively operating a selected one of the driver circuits or both, according to the signal to be reproduced, while setting an unselected driver circuit to turn either a high-side switch or a low-side switch of the unselected one of the first driver circuit or the second driver circuit fully on for at least some cycles of the one or more modulators.

A class-D amplifying system includes: a class-D amplifier circuit configured to convert an input signal to a switch control signal in pulse width modulation fashion, wherein the switch control signal controls switches to operate a first inductor and a second inductor, thus converting an input power to a positive output signal and a negative output signal which are complementary to each other, to thereby drive a load; and a power converter circuit, which generates a direct current (DC) power supply according to at least one of the positive output signal and the negative output signal, wherein the DC power supply supplies at least a portion of power to the class-D amplifier circuit.

A controller includes: a pulse-width modulation (PWM) circuit; a control loop; and a reference voltage controller. The control loop has: a feedback input adapted to be coupled to an output voltage of a power stage; a control loop output coupled to a PWM control input; and an operational amplifier with a first feedback input, a first reference input, and an amplifier output, the first feedback input connected to the feedback input, and the amplifier output coupled to the PWM control input. The reference voltage controller has a reference voltage output coupled to the first reference input, the reference voltage controller configured to adjust a reference voltage provided to the reference voltage output responsive to a dynamic error estimate based on error in the operational amplifier.

A Class-D amplifier that includes a driver stage operable in a plurality of modes having different respective output impedances, a loop filter having an output, and a circuit configured to sense a current at a load of the Class-D amplifier, determine, based on the sensed current, an IR drop for a respective output impedance of the driver stage, and add the IR drop to the loop filter output to compensate for the respective output impedance of the driver stage to reduce distortion.

A driving circuit is disclosed. The driving circuit includes a charging circuit, coupled between a voltage source and a load, configured to form a first current from the voltage source to the load; and a discharging circuit, coupled between the voltage source and the load, configured to form a second current from the load back to the voltage source.