A symbol-power-tracking (SPT) voltage supply to power a radio-frequency power amplifier (RF PA) is shown. A power converter is coupled to an output port of an input power source for power conversion, and has an output terminal coupled to a power terminal of the RF PA. A transition capacitor is coupled to the power terminal of the radio-frequency power amplifier through the output terminal of the power converter. An assisted charging and discharging circuit is coupled to the transition capacitor during cyclic prefix (CP) sections. A multi-level array is provided which includes a plurality of voltage-regulated capacitors pre-charged to and kept at different voltage levels. During each symbol section, a target capacitor at a fixed voltage level matching the current SPT situation is selected from among the voltage-regulated capacitors to be coupled to the power terminal of the radio-frequency power amplifier.

The present disclosure provides a low dropout linear voltage regulator, including: an amplifier, configured to have a first input end receiving a reference voltage, a second input end configured to receive a feedback voltage, and an output end connected to a first node; an output transistor, having a control end connected to the first node, a first end connected to a first power source potential, and a second end connected to a second node and configured to provide an output voltage; a feedback circuit, connected to the second node and configured to provide the feedback voltage according to the output voltage; and a compensation circuit, comprising at least one of a first compensation amplifier, a second compensation amplifier and a first variable current source. The compensation circuit detects and suppresses a voltage transient generated when a load switching from light to heavy occurs at the second node.

A high-frequency signal processing apparatus and a wireless communication apparatus can achieve a decrease in power consumption. For example, when an indicated power level to a high-frequency power amplifier is equal to or greater than a second reference value, envelope tracking is performed by causing a source voltage control circuit to control a high-speed DCDC converter using a detection result of an envelope detecting circuit and causing a bias control circuit to indicate a fixed bias value. The source voltage control circuit and the bias control circuit indicate a source voltage and a bias value decreasing in proportion to a decrease in the indicated power level when the indicated power level is in a range of the second reference value to the first reference value, and indicate a fixed source voltage and a fixed bias value when the indicated power level is less than the first reference value.

Techniques for efficiently generating a variable boosted supply voltage for an amplifier and/or other circuits are disclosed. In an exemplary design, an apparatus includes an amplifier, a boost converter, and a boost controller. The amplifier receives an envelope signal and a variable boosted supply voltage and provides an output voltage and an output current. The boost converter receives a power supply voltage and at least one signal determined based on the envelope signal and generates the variable boosted supply voltage based on the power supply voltage and the at least one signal. The boost controller generates the at least one signal (e.g., an enable signal and/or a threshold voltage) for the boost converter based on the envelope signal and/or the output voltage. The boost converter is enabled or disabled based on the enable signal and generates the variable boosted supply voltage based on the power supply voltage and the threshold voltage.

The present invention provides a current source comprising a first bias current control element, the first bias current control element being configured to generate a first current if the control value is lower than a reference value and configured to generate a second current if the control value equal to or higher than the reference value. In addition or alternatively the bias current source comprises a second bias current control element, the second bias current control element being configured to generate a third current if the control value is lower than or equal to the reference value and configured to generate a fourth current if the control value is higher than the reference value. Furthermore, the present invention provides an integrated circuit and a method.

In accordance with embodiments of the present disclosure, a system may include a circuit having a power converter and an amplifier, wherein the power converter is configured to generate an intermediate voltage, provide the intermediate voltage as an amplifier supply voltage to the amplifier, and share the intermediate voltage with one or more additional circuits external to the circuit, wherein at least one of the one or more additional circuits is configured to generate the intermediate voltage.

Envelope tracking systems with modeling for power amplifier supply voltage filtering are provided herein. In certain embodiments, an envelope tracking system includes a supply voltage filter, a power amplifier that receives a power amplifier supply voltage through the supply voltage filter, and an envelope tracker that generates the power amplifier supply voltage. The power amplifier provides amplification to a radio frequency (RF) signal that is generated based on digital signal data, and the envelope tracker generates the power amplifier supply voltage based on an envelope signal corresponding to an envelope of the RF signal. The envelope tracking system further includes digital modeling circuitry that models the supply voltage filter and operates to digitally compensate the digital signal data for effects of the supply voltage filter, such as distortion.

An envelope tracking (ET) power management apparatus incorporating multiple power amplifiers is provided. The ET power management apparatus includes a single ET integrated circuit (ETIC) configured to provide multiple ET voltages to the multiple power amplifiers for amplifying a radio frequency (RF) signal concurrently. The ETIC includes multiple first ET voltage circuits configured to generate multiple first ET voltages and a second ET voltage circuit configured to generate a second ET voltage. The ETIC is configured to provide each of the first ET voltages to an output stage amplifier(s) in a respective one of the power amplifiers and provide the second ET voltage to a driver stage amplifier in all of the power amplifiers. By supporting the multiple power amplifiers using a single ETIC, it is possible to reduce footprint, power consumption, and heat dissipation in an electronic device employing the ET power management apparatus.

A low frequency loss correction circuit that improves the efficiency of a power amplifier at near-DC low frequencies The low frequency loss correction circuit can include a signal error detection circuit configured to produce an error signal in response to detecting one or more frequency components of a tracking signal below a cutoff frequency that are substantially attenuated through a capacitive path. The low frequency loss correction circuit can include a drive circuit configured to convert the error signal into a low frequency correction signal, and provide the low frequency correction signal to a voltage supply line, the low frequency correction signal including at least some of the one or more frequency components of the tracking signal below a cutoff frequency that are substantially attenuated through the capacitive path.

An audio amplifier circuit for providing an output signal to an audio transducer may include a power amplifier and a control circuit. The power amplifier may include an audio input for receiving an audio input signal, an audio output for generating the output signal based on the audio input signal, and a power supply input for receiving a power supply voltage, wherein the power supply voltage is variable among at least a first supply voltage and a second supply voltage greater than the first supply voltage. The control circuit may be configured to predict, based on one or more characteristics of a signal indicative of the output signal, an occurrence of a condition for changing the power supply voltage, and responsive to predicting the occurrence of the condition, change, at an approximate zero crossing of the signal indicative of the output signal, the power supply voltage.