A switching system is connected to the power amplifier of an RF system. The switching system can switch the DC supply voltage to the power amplifier while handling the high DC current and the nanosecond switching speed requirements that are mandatory for most RF systems. The embodiments can rapidly control DC voltages but not interfere with the optimized operation of the RF transistor. The embodiments provide a desired sharp turn-on leading edge for an RF pulse while eliminating the extremely long and undesirable ramp down that typically occurs beyond the desired RF pulse period.

An apparatus and method for testing gallium nitride field effect transistors (GaN FETs) are disclosed herein. In some embodiments, the apparatus includes: a high side GaN FET, a low side GaN FET, a high side driver coupled to a gate of the high side GaN FET, a low side driver coupled to a gate of the low side GaN FET, and a driver circuit coupled to the high side and low side drivers and configured to generate drive signals capable of driving the high and low side GaN FETs, wherein the high and low side GaN FETs and transistors, within the high and low side drivers and the driver circuit, are patterned on a same semiconductor device layer during a front-end-of-line (FEOL) process.

According to one embodiment, a class-D amplifier including: a PWM modulator that outputs a PWM modulation signal in response to an input signal; and a drive circuit that amplifies the PWM modulation signal, and supplies it to an output end. The drive circuit includes: a first output transistor whose main current path is connected between a power source supplying end and the output end; a second output transistor having a size larger than a size of the first output transistor; and a resistance element that is connected between the main current path of the first output transistor and the output end.

A transmitter/receiver apparatus including: a transmitter/receiver terminal; a switching amplifier that includes a low-side switching element connected between a ground terminal and a pulse output terminal and a high-side switching element connected between the pulse output terminal and a power supply terminal and that outputs a pulse signal from the pulse output terminal; a filter that passes therethrough and outputs as a transmitted signal a predetermined frequency component of the pulse signal from a transmitter terminal; and a transmit/receive switch unit that switches the connection status between the transmitter/receiver terminal and the transmitter terminal and also switches the connection status between the transmitter/receiver terminal and a receiver terminal. During receiving, on the basis of the connection status between the transmitter/receiver terminal and the transmitter terminal, the low-side and high-side switching elements are fixed to conductive and non-conductive states, respectively, to non-conductive and conductive states, respectively, or both to non-conductive states.

Example embodiments provide a device that includes a power transformer with a first output voltage terminal providing a first voltage and a second output voltage terminal providing a second voltage, a voltage regulator coupled to one or more of the first output voltage terminal and the second output voltage terminal, and a power storage element that stores power supplied by the second output voltage, and the first output voltage terminal supplies power to a remote entity until a load power requirement of the remote entity exceeds a threshold power level at which time the power storage element is used to provide power from the second output voltage terminal to the remote entity.

An amplification circuit includes a first amplification block suitable for primarily amplifying a voltage difference between a first voltage and a second voltage corresponding to a first input current and a second input current, respectively, and a second amplification block suitable for secondarily amplifying the voltage difference between the first and second voltages to generate an amplification signal.

The present invention increases the output voltage of a switching amplifier in a situation where the power supply voltage is limited. The switching amplifier includes first and second switches that are turned on and off in a complementary manner, and a capacitance, both ends of which serve as inputs to a power combiner. Both ends of the capacitance are connected to output ends of the first and second switches. The capacitance is supplied with power along with the operation of the first and second switches. As a result, an electric charge in the capacitance is used as a charge pump, and is used alternatingly for boosting or stepping down the output voltage depending on the operation frequency of the switching amplifier, thereby generating a rectangular voltage with a controlled wave height.

The purpose of the present invention is to provide a high-power-efficiency and low-design-cost transmission device by implementing, with a constant clock, delta-sigma modulation maintaining a zero current switching property in an amplifier. This delta-sigma modulator comprises: a pulse phase signal generation unit for generating a pulse phase signal from a phase signal; a delta-sigma modulation unit for generating a pulse amplitude signal obtained by delta-sigma modulating an amplitude signal with a constant clock; a phase sorting unit for outputting a control signal on the basis of the phase signal; a delay switching unit for delaying the pulse amplitude signal on the basis of the control signal; and a mixing unit for outputting a pulse string obtained by multiplying together the delayed pulse amplitude signal and the pulse phase signal.

An improved audio amplifier system can both reduce power consumption by supporting a standby mode and shorten wake time when resuming from the standby mode. The audio amplifier system may reduce power by entering a sleep or standby state in response to a command and/or detecting that an audio input signal is not received. Further, the audio amplifier system may use a burst generator to periodically or intermittently activate the power supply during standby mode. By periodically or intermittently activating the power supply, one or more of the capacitors may be charged. By charging the capacitors during standby mode, the time to wake from standby mode may be significantly reduced. In some cases, the wake time may be reduced by several order of magnitudes (e.g., from seconds to milliseconds).

A switching power amplifier with harmonic suppression including a polyphase converter and a power amplifier stage. The polyphase converter converts a frequency or phase modulated input signal into a 50% duty cycle rail-to-rail signal, a positive 25% duty cycle rail-to-rail signal that is centered with the 50% duty cycle signal when high, and a negative 25% duty cycle rail-to-rail signal that is centered with the 50% duty cycle signal when low. The power amplifier stage includes first and second branches coupled between upper and lower nodes, each including series-coupled P-channel and N-channel transistors forming an intermediate output node. The transistors of the first branch are controlled by the 50% duty cycle signal, and the transistors of the second branch are controlled by the positive and negative 25% duty cycle signals. The first and second branches generate output currents that are superimposed with each other to suppress third and fifth harmonics.