An integrated circuit can include an amplifier coupled to receive an analog input signal, an anti-aliasing filter (AAF) coupled to an output of the amplifier, a buffer circuit coupled to an output of the AAF, a sigma-delta modulator configured to generate a digital data stream in response to an output of the buffer, and a plurality of chopping circuits nested within one another, including a first pair of chopping circuits having at least the amplifier disposed therebetween and configured to remove offset in the analog input signal, and a second pair of chopping circuit having at least the first pair of chopping circuits disposed therebetween. The amplifier, AAF, sigma-delta modulator, and chopping circuits can be formed with the same integrated circuit substrate. Corresponding methods and systems are also disclosed.

An amplifier circuit includes multiple transistors, a set of input routing circuits, and a set of output routing circuits. Each output routing circuit corresponds to an input routing circuit. Each input routing circuit and its corresponding output routing circuit are controlled by one or more control signals. Each input routing circuit is configured to selectively connect each transistor of a transistor pair to a first input terminal of the amplifier circuit, a second input terminal of the amplifier circuit, or a third input terminal of the amplifier based on a value of the one or more control signals. Each output routing circuit is configured to selectively connect each transistor of the transistor pair to a first output terminal of the amplifier circuit, a second output terminal of the amplifier circuit, or a calibration circuit based on the value of the one or more control signals.

Target voltage generation in an envelope tracking (ET) integrated circuit (ETIC) is provided. The ETIC is configured to generate a time-variant ET voltage based on a time-variant target voltage for amplifying a radio frequency (RF) signal modulated for communication in multiple time intervals. In embodiments disclosed herein, the ETIC is self-contained to generate the time-variant target voltage based on a sensed signal having a time-variant sensed envelope that tracks a time-variant power envelope of the RF signal. Since the time-variant target voltage is generated to track the time-variant sensed envelope, which further tracks the time-variant power envelope, the time-variant ET voltage can better track the time-variant power envelope of the RF signal when the time-variant ET voltage is provided to a power amplifier(s) that amplifies the RF signal.

An envelope tracking (ET) integrated circuit (ETIC) for reducing in-rush battery current is provided. The ETIC includes an ET voltage circuit configured to generate a time-variant ET voltage, which includes an offset voltage, in multiple time intervals based on a supply voltage. In some cases, the offset voltage and the supply voltage may both need to be increased or decreased as the time-variant ET voltage increases or decreases. As the offset voltage and the supply voltage increase or decrease, an excessive in-rush battery current may be generated in the ETIC to result in a reduced battery life. Hence, the ETIC is configured to avoid increasing or decreasing the offset voltage and the supply voltage in a same one of the time intervals. As a result, it is possible to reduce the in-rush battery current in the ETIC while still allowing the time-variant ET voltage to change in a timely manner.

An envelope tracking (ET) integrated circuit (ETIC) is provided. The ETIC is configured to generate an ET voltage for amplifying a radio frequency (RF) signal modulated for communication in multiple time intervals. In embodiments disclosed herein, the ETIC is self-contained to generate an ET target voltage based on a power envelope of the RF signal and to generate the ET voltage based on the ET target voltage. Given that the RF signal may be modulated at a very high modulation bandwidth, the ETIC can be configured to modify the ET target voltage in each of the time intervals to thereby cause the ET voltage to be adapted on a per time interval basis. As a result, the ET voltage can better track the power envelope of the RF signal in each of the time intervals to help improve operating efficiency of a power amplifier apparatus that employs the ETIC.

A method may include receiving, by a calibration circuit, an output of a subsystem comprising the sensor and the analog front end. The method may further include separating the output individually into the sensor offset and the amplifier offset by using inherent properties of separate frequency ranges for the sensor offset and the amplifier offset. The method may also include calibrating, by the calibration circuit, the sensor offset by determining a first calibration value for the sensor offset such that the output approximates zero during an idle-channel condition. The method may additionally include calibrating, by the calibration circuit, the amplifier offset by determining a second calibration value for the amplifier offset such that the output approximates zero during the idle-channel condition.

An operational amplifier includes a pre-amplifier circuit, a first trim circuit, and a second trim circuit. The pre-amplifier circuit is to include a differential pair and receive an input voltage. The first trim circuit is to produce an offset voltage correction current and provide the offset voltage correction current to the pre-amplifier circuit to correct an offset of the operational amplifier. The second trim circuit is to produce a common mode voltage (VCM) correction current, provide the VCM voltage correction current to the pre-amplifier circuit, and cause the VCM correction current to have a non-zero value to reduce a correction caused by the offset voltage correction current when the input voltage is within a mid voltage input range. The pre-amplifier circuit is to apply the offset correction current and the VCM correction current to output signals of the differential pair.

An integrator and an analog-to-digital converter are provided. The analog-to-digital converter includes the integrator, a comparison circuit and a control logic circuit. The integrator includes an operational amplifier, offset capacitors, input capacitors, integral capacitors and controllable switches. The input capacitors and the integral capacitors are connected to the operational amplifier via controllable switches, so that the integrator operates in various operation modes. Operation states of the offset capacitors in a first phase and a second phase of an operation cycle are controlled by switching on or off the controllable switches. Therefore, an offset voltage of the integrator is eliminated, and conversion efficiency and conversion accuracy of the analog-to-digital converter is improved.

A Doherty power amplifier circuit having a main power amplification device, an auxiliary power amplification device arranged in parallel with the main power amplification device, and a load modulation circuit comprising a harmonic injection circuit connected with respective outputs of the main power amplification device and the auxiliary power amplification device. The harmonic injection circuit is arranged to transfer harmonic components generated at the main power amplification device to the auxiliary power amplification device and harmonic components generated at the auxiliary power amplification device to the main power amplification device, when both the main and auxiliary power amplification devices are operating, for modulating the respective outputs of the main power amplification device and the auxiliary power amplification device.

Exemplary multipath digital microphones described herein can comprise exemplary embodiments of automatic gain control and multipath digital audio signal digital signal processing chains, which allow low power and die size to be achieved as described herein, while still providing a high DR digital microphone systems. Further non-limiting embodiments can facilitate switching between multipath digital audio signal digital signal processing chains while minimizing audible artifacts associated with either the change in the gain automatic gain control amplifiers switching between multipath digital audio signal digital signal processing chains.