A distributed amplifier system constituted of: an input transmission line exhibit a plurality of sections; an output transmission line; an amplifier stage, an output of the amplifier stage coupled to the output transmission line and an input of the amplifier stage coupled to the input transmission line between a respective pair of the plurality of sections; a PIN diode coupled between a first end of the input transmission line and a common potential; and a circuitry coupled between a second end of the input transmission line and the common potential, the second end opposing the first end, such that there is a direct current (DC) flow through the first unidirectional electronic valve, the input transmission line and the circuitry.

An adaptive feedback method for use in a memory device is provided. The memory device includes a first input-receiver circuit and a plurality of second input-receiver circuits. The method includes the steps of: providing a clock signal and an inverted clock signal to the first input-receiver circuit; generating an enable control signal by the first input-receiver circuit to control a first feedback path in the first input-receiver circuit; in response to the frequency of the clock signal and the inverted clock signal being higher than or equal to a predetermined frequency, activating the first feedback path in the first input-receiver circuit according to the enable control signal; and in response to the frequency of the clock signal and the inverted clock signal being lower than the predetermined frequency, deactivating the first feedback path in the first input-receiver circuit according to the enable control signal.

In some embodiments, a power amplification system can comprise a current source configured to provide a bias current, a current mirror configured to mirror the bias current, a comparator configured to compare the mirrored bias current to a threshold current, and a transistor at an output of the comparator. The transistor can be configured to be activated in response to the mirrored bias current exceeding the threshold current.

A method comprises: measuring reflected and forward power at a power amplifier output; determining if the reflected power equals to or exceeds a first level; if the reflected power is equal to or exceeds the first level, then reduce power of a power amplifier input signal; determining if a standing wave ratio at the power amplifier output equals or exceeds a second level; if the standing wave ratio at the power amplifier output equals or exceeds the second level, then reducing the power amplifier input signal power level and/or sending an alarm; determining if the power amplifier output power equals or exceeds a third level; and if the power output from the power amplifier equals or exceeds the third level, then reducing the power amplifier input signal power level until such power level is less than or equal to the third level and/or sending an alarm.

A circuit element is formed on a substrate made of a compound semiconductor. A bonding pad is disposed on the circuit element so as to at least partially overlap the circuit element. The bonding pad includes a first metal film and a second metal film formed on the first metal film. A metal material of the second metal film has a higher Young's modulus than a metal material of the first metal film.

A circuit (200) for testing failure of a connection between a radio frequency, RF, integrated circuit (201) and external circuitry (204), the circuit comprising: an amplifier (205) having first and second input paths (215, 216) and first and second output paths (206, 207); a first power detector (208, 209) coupled to one of said first or second output paths; at least one connection (211) between said first and second output paths (206, 207) and said external circuitry (204), connecting said outputs to a RF combiner (210) said external circuitry; at least one disabling circuit (230, 232, 234, 236, 240, 242, 260, 262) coupled to at least one of said first and second output paths (206, 207) or at least one of said first and second input path (215, 216), before said path reaches said power detector (208, 209); for disabling one of said inputs or outputs; wherein when said input or output path is disabled (206, 207), and a signal is output along the enabled output path (206, 207), the power detector (208, 209) on said disabled output path can detect if there is a failure in said at least one connection (211).

Systems and methods are described for a power amplifier with a tracking power supply. The power amplifier may use envelope tracking. The power amplifier is protected when the output of the power amplifier is short circuited or overloaded.

A class D audio amplifier with an output stage is provided. The class D audio amplifier includes a plurality of power transistors coupled in cascade between a first DC supply voltage and a second DC supply voltage. The class D audio amplifier also includes a plurality of gate drivers having respective inputs coupled to a modulated audio signal and configured to generate respective modulated gate drive signals to the plurality of power transistors. A first overload protection circuit includes a model transistor possessing electric characteristics representative of a first power transistor of the output stage for determining a drain-source reference voltage of the model-transistor and this drain-source reference voltage may be utilized to indicate an overload event or condition of the first power transistor.

According to one mode of the inventive concept, an amplification device includes a first amplification unit configured to amplify an input signal when a power level of the input signal is within a first range, a second amplification unit configured to amplify the input signal when the power level of the input signal is within a second range, and an abnormality sensing unit configured to sense an occurrence of an abnormality in the second amplification unit. The abnormality sensing unit senses reverse power regarding an output of the second amplification unit to generate a sensed voltage and compares the sensed voltage with a reference voltage to sense whether an abnormality occurs in the second amplification unit.

Voltage stabilizing and voltage regulating circuits implemented in GaN HEMT technology provide stable output voltages suitable for use in applications such as GaN power transistor gate drivers and low voltage auxiliary power supplies for GaN integrated circuits. Gate driver and voltage regulator modules include at least one GaN D-mode HEMT (DHEMT) and at least two GaN E-mode HEMTs (EHEMTs) connected together in series, so that the at least one DHEMT operates as a variable resistor and the at least two EHEMTs operate as a Zener diode that limits the output voltage. The gate driver and voltage regulator modules may be implemented as a GaN integrated circuits, and may be monolithically integrated together with other components such as amplifiers and power HEMTs on a single die to provide a GaN HEMT power module IC.