This disclosure describes techniques for compensating for amplifier drift. An amplifier is configured to generate an output that triggers a charge counter to generate a charge count value based on a charge count signal. A current digital-to-analog converter (IDAC) is coupled to the amplifier and configured to provide an offset current to a first input of the amplifier. An offset correction circuit is configured to: determine whether a duty cycle associated with the amplifier exceeds a specified threshold and generate a signal to cause the MAC to adjust the value of the offset current to compensate for amplifier drift based on determining whether the duty cycle exceeds the specified threshold.

A logarithmic power detector includes a power distributor, a first detection circuit, a second detection circuit and an output circuit. The power distributor is used to generate a first power signal and a second power signal according to an input signal. The first detection circuit is used to attenuate the first power signal to generate a first rectified signal, filter the first rectified signal to generate a first low-pass signal, and amplify the first low-pass signal to generate a first amplification current. The second detection circuit is used to attenuate the second power signal to generate a second rectified signal, filter the second rectified signal to generate a second low-pass signal, and amplify the second low-pass signal to generate a second amplification current. The output circuit is used to receive the first amplification current and the second amplification current to generate a converted voltage related to the input signal.

An integrated circuit includes a processor coupled to a voltage bus of a cable and located within a universal serial bus (USB) compatible power supply device. A current sense amplifier (CSA) is coupled to a sense resistor to monitor a current of the voltage bus. A first comparator is coupled to the CSA and the processor and to trigger in response to detecting that a monitored current value from the CSA is greater than or equal to a first reference value, which includes a hysteresis offset value. An analog-to-digital converter (ADC) is coupled to the CSA and the processor. In response to detecting trigger of the first comparator, the processor is to trigger the ADC to measure an absolute current value of voltage bus, and cause an additional voltage, equal to a voltage drop across the cable based on the absolute current value, to be supplied to the voltage bus.

Examples provide methods and apparatus for controlling a DC bias current in an RF amplifier. In one example where the RF amplifier is implemented on an amplifier die, a reference voltage is produced across a reference resistor implemented on the amplifier die, the DC bias current is measured, and a current controller, which is implemented on a controller die that is separate from the amplifier die, operates a feedback loop using the reference voltage to control a level of the DC bias current.

A wireless power system is described. The wireless power system includes a coil for receiving and transmitting wireless power, an integrated circuit, and one or more batteries. The integrated circuit includes a rectifier circuit, a current sense amplifier circuit, a calibration circuit, and a voltage regulator. The rectifier circuit receives alternating current from the coil and generates a rectified voltage when the wireless power system is in receive mode and further transmits alternating current to the coil when the wireless power system is in transmit mode. The current sense amplifier circuit detects a current flowing between the rectifier and the voltage regulator. The calibration circuit generates a voltage which is used by firmware of the integrated circuit to calibrate for aging of resistors within the current sense amplifier circuit.

It is disclosed an amplifier for driving a capacitive load, comprising an input terminal adapted to receive an input voltage signal, an output terminal adapted to drive the capacitive load, a linear amplification stage, switching amplification stage, a capacitor, a first switch and a measurement and control circuit. The measurement and control circuit is configured to: measure the value of the current generated at the output from the linear amplification stage and generate a driving voltage signal of the switching amplification stage; generate the first switching signal to open the first switch and generate an enabling signal to enable the operation of at least part of the switching amplification stage; generate the first switching signal to close the first switch and generate the enabling signal to disable the operation of the switching amplification stage; generate the first switching signal to open the first switch.

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.

Embodiments relate to sensing a current provided by a power supply circuit. The current sensing circuit includes a sense transistor for sensing the current provided by a main transistor, a driver for controlling a bias provided to the sense transistor and the main transistor, and a sense resistor for converting the sensed current to a voltage value. Moreover, the current sensing circuit includes a controller that modifies at least one of: (a) a resistance of the main transistor by adjusting the bias voltage provided by the driver, (b) a gain ratio between a load current and a sensing current by adjusting a number of individual devices that are active in the sense transistor, and (c) a resistance of the sense resistor.

The present disclosure relates to devices and methods for detecting and preventing occurrence of a saturation state in a power amplifier. A power amplifier module can include a power amplifier including a cascode transistor pair. The cascode transistor pair can include a first transistor and a second transistor. The power amplifier module can include a current comparator configured to compare a first base current of the first transistor and a second base current of the second transistor to obtain a comparison value. The power amplifier module can include a saturation controller configured to supply a reference signal to an impedance matching network based on the comparison value. The impedance matching network can be configured to modify a load impedance of a load line in electrical communication with the power amplifier based at least in part on the reference signal.

Methods, apparatus, systems and articles of manufacture are disclosed for current sensing and current limiting. An example apparatus includes a first main transistor including a first main transistor gate terminal coupled between an output terminal and an intermediate node; a second main transistor including a second main transistor gate terminal coupled between the intermediate node and a ground terminal; a first amplifier including a first amplifier output coupled to the first main transistor gate terminal; a second amplifier including a second amplifier output coupled to the second main transistor gate terminal; and a third amplifier including a third amplifier inverting input coupled to the intermediate node, a third amplifier non-inverting input coupled to a sense transistor, and a third amplifier output coupled to a third gate terminal of a third transistor.