A multi-bandwidth envelope tracking (ET) integrated circuit (IC) (ETIC) is provided. The multi-bandwidth ETIC may be coupled to an amplifier circuit(s) for amplifying a radio frequency (RF) signal modulated in a wide range of modulation bandwidth. In examples discussed herein, the multi-bandwidth ETIC includes an ET voltage circuit configured to generate a modulated voltage based on a supply voltage. The supply voltage may be dynamically adjusted to cause the modulated voltage to transition quickly from one voltage level to another voltage level, particularly when the RF signal is modulated in a higher modulation bandwidth, without compromising efficiency of the ET voltage circuit. As such, the multi-bandwidth ETIC may generate different modulated voltages based on the modulation bandwidth of the RF signal, thus making it possible to employ the multi-bandwidth ETIC in a wide range of wireless communication devices, such as a fifth-generation (5G) wireless communication device.

Envelope tracking systems for power amplifiers are provided herein. In certain embodiments, an envelope tracker supplies power to a power amplifier that amplifies an RF signal. The envelope tracker includes a multi-level switching circuit that generates an output current based on an envelope signal indicating an envelope of the RF signal. The envelope tracker further includes a combiner that combines a DC voltage with the output current of the multi-level switching circuit to generate a power amplifier supply voltage for the power amplifier. Accordingly, the output current of the multi-level switching circuit and a DC voltage are combined to generate the power amplifier supply voltage. Implementing the envelope tracking system in this manner can provide enhanced efficiency and/or higher bandwidth relative to an envelope tracking system in which a multi-level switching circuit directly outputs a power amplifier supply voltage.

A power supply apparatus including a signal generator circuit configured to generate a plurality of power supply signals via at least one DC-to-DC converter, the plurality of power supply signals including a first power supply signal on a first output path and a second power supply signal on a second output path that is independent of the first output path, the first power supply signal being different from the second power supply signal. The apparatus includes a switching circuit to provide during a first operating mode, a first combined power supply signal on the first output path based on the first power supply signal and a third power supply signal of the plurality of power supply signals. The switching circuit provides during a second operating mode, a second combined power supply signal on the second output path based on the second power supply signal and the third power supply signal.

Disclosed herein are circuits, devices and methods that address challenges associated with power amplifier systems. A power amplifier system includes two or more fast error amplifiers coupled to corresponding power amplifiers. The fast error amplifiers are configured to generate envelope tracking signals based on a signal envelope, the envelope tracking signals modifying a DC-DC regulated voltage from a DC-DC converter to more efficiently operate the power amplifiers. By splitting the envelope tracking between two or more fast error amplifiers and amplification between corresponding two or more power amplifiers, the power, frequency or bandwidth, linearity, signal-to-noise ratio, efficiency, or the like of the power amplifier system can be improved. Wireless communications configurations with such power amplifier systems can provide uplink carrier aggregation and/or cellular signals based on standards and protocols that require increased bandwidth and/or power.

Envelope tracking can be employed to reduce power consumption of a power amplifier, but envelope tracking can introduce nonlinearities to a power amplifier. These nonlinearities can manifest themselves as noise at the output of the power amplifier. Embodiments described herein provide techniques for characterizing a parameter indicative of power amplifier noise when envelope tracking is employed. Measurement of this parameter can permit power amplifier designers to decide whether to forgo envelope tracking if a power amplifier is too susceptible to such noise, redesign the power amplifier to improve compatibility with envelope tracking, or to employ distortion compensation circuitry to reduce the noise output by the power amplifier. Counterintuitively, this distortion compensation circuitry may involve increasing the power, such as the envelope tracking power supply. However, increasing the power may be a desirable trade-off for increased linearity.

An envelope tracking (ET) power amplifier apparatus is provided. In a non-limiting example, the ET power amplifier apparatus includes a single ET integrated circuit (ETIC) configured to support at least a pair of amplifier circuits for amplifying different radio frequency (RF) signals. One of the amplifier circuits may be configured to amplify a respective RF signal to a higher power and thus will operate based on an ET voltage whenever possible. Another amplifier circuit, on the other hand, may be configured to amplify a respective RF signal to a relatively lower power and thus will only operate based on the ET voltage when the other amplifier circuit is inactive. By employing a single ETIC, it may be possible to reduce footprint of the ET power amplifier apparatus, thus making it possible to fit the ET power amplifier apparatus into a small form factor electronic device, such as a wearable device.

Doherty amplifier having envelope control. In some embodiments, an amplifier system can include a Doherty amplifier having a carrier amplifier and a peaking amplifier, with each of the carrier amplifier and the peaking amplifier including a cascode stage with input and output transistors arranged in a cascode configuration. The amplifier system can further include an envelope tracking bias circuit coupled to the Doherty amplifier and configured to provide a bias signal to the output transistor of the cascode stage of the peaking amplifier.

Quadrature amplifier having envelope control. In some embodiments, an amplifier system can include a quadrature amplifier having first and second amplifiers configured to amplify first and second signals in quadrature relative to each other, with each of the first and second amplifiers including a cascode stage with input and output transistors arranged in a cascode configuration. The amplifier system can further include an envelope tracking bias circuit coupled to the quadrature amplifier and configured to provide a bias signal to the output transistor of the cascode stage of at least one of the first and second amplifiers.

A low-power wake-up receiver. The receiver includes a transformer/filter resonating at a pre-selected frequency to realize passive RF voltage gain. A pseudo-balun envelope detector is coupled to an output of the transformer filter. A comparator or other quantizer is coupled to an output of the active pseudo-balun envelope detector (ED) for comparing the ED output to a comparison threshold voltage. The pseudo-balun envelop detector can be an active detector. The pseudo-balun detector can also be a passive detector.

Various embodiments disclose a method and a device including: an antenna, a switching regulator, communication chip including an amplifier and a linear regulator operably connected to the amplifier and the switching regulator, the communication chip configured to transmit a radio-frequency signal from the electronic device through the antenna, and control circuitry configured to control the communication chip such that the linear regulator provides the amplifier with a voltage corresponding to an envelope of an input signal input to the amplifier, the input signal corresponding to the radio-frequency signal.