A protection circuit for an acoustic filter and/or a power amplifier is disclosed. In one aspect, the protection circuit includes a bidirectional coupler that helps secure a measurement of power at an antenna. The power measurement is compared to a threshold by a detector, and if the power measurement is above the threshold, a signal is sent that causes debiasing of a power amplifier stage, which reduces power levels of signals being amplified by the power amplifier stage and correspondingly lowers the power level going through a filter associated with the power amplifier stage. By lowering the power level going through the power amplifier stage and the filter, both elements are protected against over power conditions allowing functionality to be maintained.

A protection circuit for an acoustic filter and/or a power amplifier is disclosed. In one aspect, the protection circuit includes a bidirectional coupler that helps secure a measurement of power at an antenna. The power measurement is compared to a threshold by a detector, and if the power measurement is above the threshold, a signal is sent that causes debiasing of a power amplifier stage, which reduces power levels of signals being amplified by the power amplifier stage and correspondingly lowers the power level going through a filter associated with the power amplifier stage. By lowering the power level going through the power amplifier stage and the filter, both elements are protected against over power conditions allowing functionality to be maintained.

A power amplifier with feedback ballast resistance is disclosed. In one aspect, a power amplifier cell may receive a bias signal from a bias circuit where the bias circuit includes a feedback loop having an impedance that, from the perspective of the bias signal is relatively low impedance, but from a ballast thermal control perspective provides sufficient resistance to avoid thermal runaway. In exemplary aspects, this feedback loop may be extended to operate with multiple power amplifier cells and provide differential mode thermal control optimized for individual cell bias signal control and common mode thermal control optimized for thermal control of the collective power amplifier cells of the power amplifier.

A method of operating a driver circuit includes receiving a data signal at a first input of an amplification circuit; amplifying, using the amplification circuit, the data signal to produce an output signal through an output pin; attenuating, using a feedback network, the output signal to produce a feedback signal; coupling the feedback signal to a second input of the amplification circuit; detecting, using a control circuit, a fault condition; and decoupling, responsive to detecting the fault condition, the feedback signal from the second input of the amplification circuit. In some embodiments, the driver circuit transmits a fault condition signal to an electronic control unit of an automobile.

A method of operating a driver circuit includes receiving a data signal at a first input of an amplification circuit; amplifying, using the amplification circuit, the data signal to produce an output signal through an output pin; attenuating, using a feedback network, the output signal to produce a feedback signal; coupling the feedback signal to a second input of the amplification circuit; detecting, using a control circuit, a fault condition; and decoupling, responsive to detecting the fault condition, the feedback signal from the second input of the amplification circuit. In some embodiments, the driver circuit transmits a fault condition signal to an electronic control unit of an automobile.

Concurrent electrostatic discharge and surge protection clamps in power amplifiers. In some embodiments, a semiconductor die can include a semiconductor substrate and an integrated circuit implemented on the semiconductor substrate. The integrated circuit can include a power amplifier and a controller. The semiconductor die can further include a clamp circuit implemented on the semiconductor substrate and configured to provide electrostatic discharge protection and surge protection for at least some of the integrated circuit.

An amplifying circuit is provided. The amplifying circuit includes a bias circuit receiving an operating voltage from a power supply circuit and generating a first bias voltage, a resistance circuit connected between the bias circuit and a gate node and transferring the first bias voltage to the gate node, a start-up circuit generating a high-level start-up voltage and supplying the start-up voltage to the gate node before the operating voltage is supplied, based on a control signal, and an amplifier started-up by receiving the start-up voltage and then receiving the operating voltage and the first bias voltage to amplify a high frequency signal input through the gate node.

A circuit for driving a capacitive load includes an amplifier for driving the load based on an input signal, the amplifier comprising at least a boost converter, a dynamic model configured to track a capacitance of the load and a voltage of the source for powering at least parts of the circuit, an adaptive filter, configured to filter the input signal based on an output of the dynamic model.

An amplifier circuit including a semiconductor element is formed on a substrate. A protection circuit is formed including a plurality of protection diodes that are formed on the substrate and that are connected in series with each other, the protection circuit being connected to an output terminal of the amplifier circuit. A pad conductive layer is formed that at least partially includes a pad for connecting to a circuit outside the substrate. An insulating protective film covers the pad conductive layer. The insulating protective film includes an opening that exposes a partial area of a surface of the pad conductive layer, and that covers another area. A first bump is formed on the pad conductive layer on a bottom surface of the opening, and a second bump at least partially overlaps the protection circuit in plan view and is connected to a ground (GND) potential connected to the amplifier circuit.

An amplifier circuit including a semiconductor element is formed on a substrate. A protection circuit is formed including a plurality of protection diodes that are formed on the substrate and that are connected in series with each other, the protection circuit being connected to an output terminal of the amplifier circuit. A pad conductive layer is formed that at least partially includes a pad for connecting to a circuit outside the substrate. An insulating protective film covers the pad conductive layer. The insulating protective film includes an opening that exposes a partial area of a surface of the pad conductive layer, and that covers another area. A first bump is formed on the pad conductive layer on a bottom surface of the opening, and a second bump at least partially overlaps the protection circuit in plan view and is connected to a ground (GND) potential connected to the amplifier circuit.