Power amplifiers having reduced loss. In some embodiments, a power amplification system can include a plurality of power amplifiers, with each power amplifier being configured to receive and amplify a signal in a frequency band. The power amplification system can further include an output filter coupled to each of the power amplifiers by a separate output path such that the power amplification system is substantially free of a band selection switch between the plurality of power amplifiers and their corresponding output filters. Each power amplifier can be further configured to operate with a high-voltage supply to provide an impedance similar to an impedance of the corresponding output filter.

The representative embodiments discussed in the present disclosure relate to techniques in which the operating characteristics (e.g., gain and/or efficiency) of a power amplifier in a transmitter may be regulated according to an operation mode of the transmitter. More specifically, in some embodiments, different look-up tables (LUTs) may be employed for each mode of operation to suitably adjust the supply voltage to the power amplifier and modulate its operating characteristics based on power input to the power amplifier. Further, in some embodiments, a method to calibrate a LUT for uplink carrier aggregation (ULCA) operation mode of the transmitter may be employed to populate a LUT used to suitably adjust the supply voltage during ULCA.

Embodiments of the disclosure relate to a multi-mode power management system supporting fifth-generation new radio (5G-NR). The multi-mode power management system includes first tracker circuitry and second tracker circuitry each capable of supplying an envelope tracking (ET) modulated or an average power tracking (APT) modulated voltage. In examples discussed herein, the first tracker circuitry and the second tracker circuitry have been configured to support third-generation (3G) and fourth-generation (4G) power amplifier circuits in various 3G/4G operation modes. The multi-mode power management system is adapted to further support a 5G-NR power amplifier circuit(s) in various 5G-NR operation modes based on the existing first tracker circuitry and/or the existing second tracker circuitry. In this regard, the 5G-NR power amplifier circuit(s) can be incorporated into the existing multi-mode power management system with minimum hardware changes, thus enabling 5G-NR support without significantly increasing component count, cost, and footprint of the multi-mode power management system.

A system includes an input port having an input voltage, an output port having an output voltage, and a power converter having a switch network with a plurality of power switches and a first resonant tank having a first resonant capacitor and a first resonant inductor, where at least one resonant component within the first resonant capacitor and the first resonant inductor is a switchable component configured to switch between different values. The system further includes a resonant mode selection block configured to adjust a value of the switchable component to maintain a performance of the system, and a controller configured to adjust a switching frequency or a duty cycle of the power converter.

An apparatus for detecting difference in operating characteristics of a main circuit by using a replica circuit is presented. In one exemplary case, a sensed difference in operating characteristics of the two circuits is used to drive a tuning control loop to minimize the sensed difference. In another exemplary case, several replica circuits of the main circuit are used, where each is isolated from one or more operating variables that affect the operating characteristic of the main circuit. Each replica circuit can be used for sensing a different operating characteristic, or, two replica circuits can be combined to sense a same operating characteristic.

A sound producing apparatus is provided. The sound producing apparatus includes a driving circuit, configured to generate a driving signal according to an input audio signal; and a sound producing device; wherein the sound producing device is driven by the driving signal, such that the sound producing device produces a plurality of air pulses at an air pulse rate, the air pulse rate is higher than a maximum human audible frequency; wherein the plurality of air pulses produces a non-zero offset in terms of sound pressure level, and the non-zero offset is a deviation from a zero sound pressure level; wherein the driving signal driving the sound producing device to produce the plurality of air pulses, is unipolar with respect to a first voltage.

An envelope tracking device includes a fine slot peak tracking (FSPT) circuit, at least one power amplifier, and an envelope modulator. The FSPT circuit is connected to the power amplifier through the envelope modulator. The FSPT circuit generates envelope signals based on input signals, adds an offset to the envelope signals, and expands and smoothes the added envelope signals. The envelope modulator generates envelope voltage signals according to the smoothed envelope signals, and outputs the signals to drain of the power amplifier. The envelope voltage signals are time-aligned with the amplified signals which are transmitted to gate of the power amplifier.

Techniques are described for using valley detection for supply voltage modulation in power amplifier circuits. Embodiments operate in context of a power amplifier circuit configured to be driven by a supply voltage generated by a supply modulator and to receive an amplitude-modulated (AM) signal at its input. The output of the power amplifier circuit can be fed to a valley detector that can detect a valley level corresponding to the bottom of the envelope of the AM signal. The detected valley level can be fed back to the supply modulator and compared to a constant reference. In response to the comparison, the supply modulator can vary the supply voltage to the power amplifier circuit in a manner that effectively tracking the envelope of the power amplifier circuit's output signal, thereby effectively seeking a flat valley for the output signal's envelope.

An envelope tracking (ET) integrated circuit (IC) (ETIC) is provided. The ETIC includes a number of ET circuits configured to generate a number of ET voltages based on a number of ET target voltages, respectively. In examples discussed herein, a selected ET circuit among the ET circuits is configured to generate a respective ET voltage based on a maximum ET target voltage among the ET target voltages. In this regard, the respective ET voltage generated by the selected ET circuit can be used as a reference ET voltage for the rest of the ET circuits in the ETIC. As a result, it may be possible to opportunistically turn off or reduce functionality of one or more other ET circuits in the ETIC, thus helping to reduce peak battery current and improve heat dissipation in an ET amplifier apparatus incorporating the ETIC.

Bias circuits and methods for silicon-based amplifier architectures that are tolerant of supply and bias voltage variations, bias current variations, and transistor stack height, and compensate for poor output resistance characteristics. Embodiments include power amplifiers and low-noise amplifiers that utilize a cascode reference circuit to bias the final stages of a cascode amplifier under the control of a closed loop bias control circuit. The closed loop bias control circuit ensures that the current in the cascode reference circuit is approximately equal to a selected multiple of a known current value by adjusting the gate bias voltage to the final stage of the cascode amplifier. The final current through the cascode amplifier is a multiple of the current in the cascode reference circuit, based on a device scaling factor representing the relative sizes of the transistor devices in the cascode amplifier and in the cascode reference circuit.