A power amplifier with clamp and feedback protection circuitry is disclosed. In one aspect, the power amplifier is initially protected by a fast-acting clamp circuit whose overall size is relatively limited. Subsequent operation allows a comparatively slowly acting feedback loop to dominate the protection of the power amplifier. By providing the two protection circuits, each optimized for a particular phase of protection, the overall size of associated protection circuitry may be diminished while still protecting the power amplifier from failure inducing conditions.

An amplification circuit includes: an amplifier including a transistor that is connected between an input terminal and an output terminal; an input matching network that is connected between the input terminal and an input side of the amplifier and converts an impedance from a low impedance to a high impedance; a limiter circuit that is connected between a node between the input matching network and the input side of the amplifier, and ground and includes two diodes connected in opposite directions to each other; and a capacitor that is connected in series with the limiter circuit between the node and ground.

The present disclosure relates to a full-bridge class D amplifier comprising a first and second half-bridge circuit, wherein each half-bridge comprises a half-bridge output terminal between a high-side switch and a low-side switch. Wherein the first and second half-bridge circuits are controlled by a respective control signal to operate in differential mode with a predetermined switching frequency and wherein each half-bridge circuit further comprises an output terminal inductor connected between the half-bridge output terminal and ground. The amplifier further comprises a first and second coil coupled to form a common mode choke, wherein the first half-bridge output terminal is connected to an input terminal of the first coil, and wherein the second half-bridge output terminal is connected to an input terminal of the second coil .

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 overvoltage protection circuit includes an input terminal, an output terminal, a clamp transistor, and a selector circuit. The clamp transistor is configured to control current flow between the input terminal and the output terminal. The clamp transistor includes a first terminal coupled to the input terminal, a second terminal coupled to the output terminal. The selector circuit is configured to control a resistance of the clamp transistor based on a voltage at the input terminal. The selector circuit includes a first terminal coupled to the first terminal of the clamp transistor, a second terminal coupled to the second terminal of the clamp transistor, and a third terminal coupled to a third terminal of the clamp transistor.

A high-frequency power amplifier is configured in such a way as to include an input matching circuit, an amplifying element, an output matching circuit, a coupling circuit, a detection circuit, and an output terminal, and in such a way that either the input matching circuit or the output matching circuit has an active element, the detection circuit receives a signal outputted by the coupling circuit and outputs a control voltage into which the detection circuit converts the signal to the active element, and the active element changes the impedance of the active element in accordance with the control voltage outputted by the detection circuit, thereby changing the power of a signal outputted by either the input matching circuit having the active element or the output matching circuit having the active element, to change the power of a signal which the coupling circuit outputs to the output terminal.

Radio frequency amplifiers with overload protection are provided herein. In certain configurations, an RF amplifier system includes an RF amplifier that receives an RF signal from an input terminal and that generates an amplified RF signal at an output terminal, and an overload detection circuit that generates a detection signal indicating a detected signal level of the RF amplifier. The RF amplifier includes an amplification device that amplifies the RF signal and a degeneration circuit that provides degeneration to the amplification device. Additionally, the detection signal is operable to control an amount of degeneration provided by the degeneration circuit so as to protect the RF amplifier from overload.

An integrated circuit includes a multiplexer circuit configured to provide an output signal on a conductive line, a programmable gain amplifier having a non-inverting input connected to the conductive line to receive the output signal from the multiplexer, a slew rate adjust circuit connected at a first node on the conductive line between the multiplexer circuit and the programmable gain amplifier, a first switch including a first terminal connected to the first node and a second terminal connected to the input of the programmable gain amplifier, and a low pass filter connected between the first and second terminals of the first switch.

An amplifier circuit including an input amplifier, an output amplifier and a diode device is provided. The output amplifier includes a PMOSFET and an NMOSFET. The PMOSFET has a gate electrode serving as a first input end and a drain coupled to an output end. The NMOSFET has a gate electrode serving as a second input end and a drain coupled to the output end. The output amplifier outputs an output voltage at the output end, and is coupled to the input amplifier via at least one of the first and second input ends. The diode device is coupled between the output end and the at least one of the first and second input ends of the output amplifier. When a voltage difference between the output end and the at least one of the first and second input ends of the output amplifier is greater than a barrier voltage of the diode device, the diode device is turned on, and an overshoot of the output voltage is reduced.

Radio frequency (RF) amplifiers with overload protection are provided herein. In certain configurations, an RF amplifier system includes an RF amplifier that receives an RF signal from an input terminal. The RF amplifier includes an amplification field-effect transistor (FET) having a gate that receives the RF signal, and a degeneration circuit connected between a source of the amplifier FET and a ground voltage. The RF amplifier system further includes an electrostatic discharge protection circuit including a plurality of protection diodes electrically connected in series between the input terminal and the ground voltage, and a detector having an input connected along an electrical path through the plurality of protection diodes and an output that generates a detection signal operable to control an amount of degeneration provided by the degeneration circuit.