A switching amplifier provided, at a minimum, with: a first input transistor into which one of two input signals that operate in a complementary manner is input; a first cascode transistor cascade-connected between the first input transistor and a power supply; a second input transistor into which the other of the two input signals is input; and a second cascode transistor cascade-connected between the second input transistor and the first input transistor; the switching amplifier extracting an output signal, a connection point between the first input transistor and the second cascode transistor being used as an output terminal; wherein a first potential limiting circuit and a second potential limiting circuit for limiting the potential fluctuation range are respectively connected to the input terminal of the first cascode transistor and the input terminal of the second cascode transistor.

A magnetic resonance wireless power transmission device capable of adjusting resonance frequency is disclosed. A wireless power transmission device according to an embodiment of the present invention comprises: a power amplifier for amplifying a wireless power signal using a driving frequency signal; a resonator for configuring a resonance tank and wirelessly transmitting, through magnetic resonance, the wireless power signal output from the power amplifier using a resonance frequency of the resonance tank; and a resonance control unit for controlling a duty ratio using a frequency applied to the resonator or a frequency signal generated by the resonator and adjusting the resonance frequency of the resonator.

An electric power converter includes a first capacitor being located between an input terminal and an output terminal, and that connects a first terminal being located between the input terminal and a ground, a reactor that connects through electric contact between the first terminal and the output terminal, a switching element that connects through electric contact between the input terminal and the output terminal, and a control unit that executes a first PWM control process controlling a pulse width of the PWM waveform by on and off of the switching device according to the fluctuation of the output voltage, and that executes a second PWM control process widening a pulse width of the PWM and a duty cycle of a PWM than those of the previous cycle when a pulse width becomes a lower limit.

An electric power converter includes a first capacitor being located between an input terminal and an output terminal, and that connects a first terminal being located between the input terminal and a ground, a reactor that connects through electric contact between the first terminal and the output terminal, a switching element that connects through electric contact between the input terminal and the output terminal, and a control unit that executes a first PWM control process controlling a pulse width of the PWM waveform by on and off of the switching device according to the fluctuation of the output voltage, and that executes a second PWM control process widening a pulse width of the PWM and a duty cycle of a PWM than those of the previous cycle when a pulse width becomes a lower limit.

A transmitter, a transmission system and a transmission method whereby AM-PM distortions can be compensated with high accuracy without affecting the functions of a predistortor, a ΔΣ modulator and so on. The transmitter includes: a baseband signal generation circuit that outputs the amplitude value and phase value of a baseband signal; a ΔΣ modulation circuit that performs a ΔΣ modulation of the outputted amplitude and phase values to output a pulse signal train; a power supply modulation circuit that supplies, to a pre-stage amplifier, a voltage determined in accordance with the outputted amplitude value; the pre-stage amplifier and a post-stage amplifier that amplify the outputted pulse signal train; and a filter circuit that generates an output signal from the pulse signal train as amplified and outputs the output signal. The power supply modulation circuit determines the voltage for canceling a phase error occurring in the post-stage amplifier.

A transmitter, a transmission system and a transmission method whereby AM-PM distortions can be compensated with high accuracy without affecting the functions of a predistortor, a ΔΣ modulator and so on. The transmitter includes: a baseband signal generation circuit that outputs the amplitude value and phase value of a baseband signal; a ΔΣ modulation circuit that performs a ΔΣ modulation of the outputted amplitude and phase values to output a pulse signal train; a power supply modulation circuit that supplies, to a pre-stage amplifier, a voltage determined in accordance with the outputted amplitude value; the pre-stage amplifier and a post-stage amplifier that amplify the outputted pulse signal train; and a filter circuit that generates an output signal from the pulse signal train as amplified and outputs the output signal. The power supply modulation circuit determines the voltage for canceling a phase error occurring in the post-stage amplifier.

Disclosed examples include a radar system that operates in a first mode and a second mode. In the first mode, the system detects the presence of an object within a threshold range. In response to detection of the presence of the object, the system transitions to the second mode, and the system generates range data, velocity data, and angle data of the object in the second mode. When the object is no longer detected within the threshold range, the system transitions back to the first mode.

Apparatuses, systems, and methods for a digital power amplifier (DPA) to generate a monotonic and linear ramp-up and ramp-down for a time division multiple access (TDMA) slot transmission are described. In one aspect, a monotonic and linear amplitude-to-control input code relationship model is generated for the DPA and stored. When the DPA needs to generate a ramp-up or ramp-down, the stored monotonic and linear amplitude-to-control input code relationship model is used to shape the input control code before it is input into the DPA. A new monotonic and linear amplitude-to-control input code relationship model may be generated and stored if the operating conditions change. The apparatuses, systems, and methods described herein may be applied to a multi-standard broadband modem chip capable of 2G transmission.

A pulse shaping circuit is configured to shape a waveform of an edge of a signal applied to a switch of a power amplifier included in an on-off keying transmitter.

A self-oscillating class D amplifier includes an integration circuit configured to integrate an input signal and output a result of the integration as an integrated signal, a comparator configured to receive the integrated signal at an inverting input terminal and output a pulse width modulation signal by comparing voltages of a non-inverting input terminal being grounded and the inverting input terminal, a switching circuit configured to power-amplify the pulse width modulation signal output from the comparator, a low-pass filter configured to extract an amplified output signal from the power-amplified pulse width modulation signal, a first feedback circuit configured to feed back the output signal of the low-pass filter to the inverting input terminal of the comparator, and a second feedback circuit configured to feed back the output signal of the low-pass filter to the integration circuit.