A method, applied in a driving circuit including a bidirectional circuit coupled between a voltage source and a load, includes receiving a feedback signal from the load and an input signal; generating a plurality of pulse width modulation (PWM) signals according to the input signal and the feedback signal; driving the load by the bidirectional circuit according to the plurality of PWM signals such that the input signal and the feedback signal are substantially proportional to each other. The input signal is a time varying signal. The step of generating a PWM signal among the plurality of PWM signals according to the input signal and the feedback signal includes determining a difference according to the input signal and the feedback signal; and generating the PWM signal with a pulse width. The pulse width is determined according to the difference.

The technology described in this document can be embodied in an audio power amplifier that includes a first channel and a second channel. Each of the first channel and the second channel includes an input to receive an input signal, a pair of switching devices, drive circuitry for driving the pair of switching devices to produce a signal, and an output filter to filter the signal from the pair of switching devices. The output filter is configured to provide the filtered signal to an audio load. Each of the first channel and the second channel includes a voltage feedback loop to provide a voltage of the filtered signal to a voltage controller of the audio power amplifier, and a current feedback loop to provide a current of the filtered signal to a current controller of the audio power amplifier. The audio power amplifier includes a summer for combining the input of the first channel and the input of the second channel when an output of the first channel is connected to an output of the second channel.

A signal receiver includes a data sampler receiving a differential input signal having first and second input signals and determining bit values of the differential input signal based on first and second reference voltages, and a reference voltage generator performing a pre-tuning operation and a post-tuning operation to generate the reference voltages. The reference voltage generator performs the pre-tuning operation by generating first and second initial voltages and adjusting one of the initial voltages to generate third and fourth voltages. After the pre-tuning operation, the reference voltage generator performs the post-tuning operation by increasing or decreasing the third voltage to generate the first reference voltage and decreasing or increasing the fourth voltage to generate the second reference voltage based on a comparison result between the third voltage and the first input signal and a second comparison result between the fourth voltage and second input signal.

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.

According to certain aspects, a predictive tracking scheme is provided for sampling inductor currents in a digital PWM controller used for high-bandwidth voltage regulation. In one or more embodiments, the predicted current derived from the PWM waveform is fed forward to the current sense ADC in order to reduce the required conversion range. These and other embodiments only need to convert a few of the LSB of the ADC in order to correct the largest error expected in the synthesizer.

A method applied in a driving circuit is disclosed. The driving circuit is coupled between a voltage source and a load and configured to drive the load. The method includes: forming, by the driving circuit, a first current from the voltage source to the load; and forming, by the driving circuit, a second current from the load back to the voltage source.

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.

A method applied in a driving circuit is disclosed. The driving circuit is coupled between a voltage source and a load and configured to drive the load. The method includes: forming, by the driving circuit, a first current from the voltage source to the load; and forming, by the driving circuit, a second current from the load back to the voltage source.

A multimode envelope tracking (ET) circuit and related apparatus is provided. The multimode ET circuit is configured to provide an ET voltage(s) to an amplifier circuit(s) for amplifying a radio frequency (RF) signal(s) that may correspond to a wider range of modulation bandwidth. In this regard, the multimode ET circuit is configured to switch dynamically and opportunistically between different operation modes based on the modulation bandwidth of the RF signal(s). In examples discussed herein, the multimode ET circuit is configured to support a single amplifier circuit in a high-modulation-bandwidth mode and an additional amplifier circuit(s) in a mid-modulation-bandwidth mode and a low-modulation-bandwidth mode. By switching dynamically and opportunistically between different operation modes, it may be possible to reduce undesired series resonance that may cause distortion in the ET voltage(s), thus helping to improve efficiency and performance of the amplifier circuit(s) supported by the multimode ET circuit.

The present invention relates to a multi-level class D audio power amplifier for supplying an N-level drive signal to a loudspeaker. The multi-level class D audio power amplifier further comprises a switching matrix comprising a plurality of controllable semiconductor switches where the switching matrix comprising at least (N−2) switch inputs, coupled to respective ones of (N−2) DC input voltage nodes, and at least 2*(N−2) switch outputs coupled to respective ones of 2*(N−2) intermediate nodes of a first output driver. A control circuit is configured to sequentially connect each of the (N−2) DC input voltages to a predetermined set of nodes of the 2*(N−2) intermediate nodes of the first output driver via the switching matrix in accordance with one or more of the 2*(N−1) modulated control signals of the first output driver. N is a positive integer larger than or equal to 3.