A current sensing circuit having self-calibration includes two leads, a sensing element having a sensing resistance, and a sensing and calibration circuit. The sensing and calibration circuit senses and calibrates a sensing voltage of the sensing element, and senses a sensing current through the sensing element according to the sensing resistance and the sensing voltage, to generate a current sensing output signal. The sensing and calibration circuit includes two pads, a V2I circuit, a current mirror circuit and an I2V circuit. The sensing element has a first temperature coefficient (TC). The TC and/or the resistance of an adjusting resistor in the V2I circuit and an adjusting resistor in the I2V circuit are determined according to the first TC, such that the TC of the current sensing output signal is equal to 0.

A system may include a Class-D stage comprising a first high-side switch coupled between a supply voltage and a first output terminal of the Class-D stage, a second high-side switch coupled between the supply voltage and a second output terminal of the Class-D stage, a first low-side switch coupled between a ground voltage and the first output terminal, and a second low-side switch coupled between the ground voltage and the second output terminal. The system may also include current sensing circuitry comprising a first sense resistor coupled between the first low-side switch and the ground voltage, such that an output current through a load coupled between the first output terminal and the second output terminal causes a first sense voltage proportional to the output current across the first sense resistor when the first low-side switch is activated. The current sensing circuitry may also include a second sense resistor coupled between the second low-side switch and the ground voltage, such that an output current through the load causes a second sense voltage proportional to the output current across the second sense resistor when the second low-side switch is activated. The system may also include measurement circuitry configured to measure the first sense voltage and the second sense voltage to determine the output current.

A switching amplifier comprises a controller, configured to receive an input signal and a reference signal, and to generate a control signal according to the input signal and the reference signal; a pulse-width modulation (PWM) modulator, coupled to the controller, configured to generate a PWM signal according to the input signal and the control signal; a power management unit, coupled to the controller, configured to receive a power supply and the control signal, and to provide an adaptive supply voltage according to the power supply and the control signal; and a switching power stage, coupled to the power management unit and the PWM modulator, configured to generate an output signal according to the PWM signal and the adaptive supply voltage.

An amplifying apparatus is provided, which includes a power-source main line, a plurality of amplifying control devices which include an amplifier, a power-source branch line, an over current protector. The amplifier amplifies a high-frequency signal. The power-source branch line is branched from the power-source main line. The over current protector disposed for the power-source branch line is connected to the amplifier and configured to disconnect the power-source branch line based on drive current flowing through the amplifier from the power-source branch line. The power-source main line is common to the plurality of amplifying control devices.

A system may include a Class-D stage comprising a first high-side switch coupled between a supply voltage and a first output terminal of the Class-D stage, a second high-side switch coupled between the supply voltage and a second output terminal of the Class-D stage, a first low-side switch coupled between a ground voltage and the first output terminal, and a second low-side switch coupled between the ground voltage and the second output terminal. The system may also include current sensing circuitry comprising a sense resistor, such that an output current through a load coupled between the first output terminal and the second output terminal causes a first sense voltage proportional to the output current across the sense resistor. The system may additionally include a modulator for generating a differential pulse-width modulation driving signal to the first high-side switch, the second high-side switch, the first low-side switch, and the second low-side switch and pilot tone injection circuitry configured to inject a periodic pilot tone into the differential pulse-width modulation driving signal at a pilot tone frequency.

Techniques for generating a power tracking supply voltage for a circuit (e.g., a power amplifier) are disclosed. The circuit may process multiple transmit signals being sent simultaneously on multiple carriers at different frequencies. In one exemplary design, an apparatus includes a power tracker and a power supply generator. The power tracker determines a power tracking signal based on inphase (I) and quadrature (Q) components of a plurality of transmit signals being sent simultaneously. The power supply generator generates a power supply voltage based on the power tracking signal. The apparatus may further include a power amplifier (PA) that amplifies a modulated radio frequency (RF) signal based on the power supply voltage and provides an output RF signal.

A circuit includes a field effect transistor (FET), a reference transistor having an output coupled to an output of the FET, an active bias circuit coupled to the reference transistor and configured to generate an input signal for the reference transistor in response to a change in drain current of the reference transistor due to carrier trapping and to apply the input signal to an input of the reference transistor, and a summing node coupled to an input of the FET and to the input of the reference transistor. The summing node adds the input signal to an input signal of the FET to compensate the carrier trapping effect.

The present document describes an error amplification circuit for a voltage regulator. The error amplification circuit comprises a differential error amplifier having a first input for a feedback signal of the voltage regulator and having a second input for a reference signal, wherein the differential error amplifier is configured to provide an amplifier output current in dependence of the signals at the first input and at the second input. Furthermore the error amplification circuit comprises a current sensing unit configured to sense the amplifier output current to provide a sensed current, a processing unit configured to process the sensed current to provide a processed current, and an adjustment resistor which is arranged in series with the second input of the differential error amplifier and to which the processed current is applied.

This invention relates to current sensing, in particular for a signal processing circuit (500) for outputting an output signal (Sout) based on an input signal (Sin). An output stage (101) includes an output transistor (102) driven, in use, by a drive signal. A current monitor (501) is configured to monitor, in use, a first current through the output transistor, wherein the current monitor comprises a current sensor (105) having a sense transistor (106) configured to be driven based on the drive signal so as to generate a sense current related to the first current. A compensation controller (301) receives an indication of signal level of the input signal and controllably varies operation of the current monitor (501) so as to at least partially compensate for signal-dependent variation in a relationship between the first current and the first sense current.

A system for sensing an electrical quantity may include a sensing stage configured to sense the electrical quantity and generate a sense signal indicative of the electrical quantity, wherein the electrical quantity is indicative of an electrical signal generated by a Class-DG amplifier configured to drive a load wherein the Class-DG amplifier has multiple signal-level common modes and a common-mode compensator configured to compensate for changes to a common-mode voltage of a differential supply voltage of the driver occurring when switching between signal-level common modes of the Class-DG amplifier.