Renesas Electronics Corporation

Masakazu Mizokami

Tomohiro Sano

Yoshikazu Furuta

Kenji Toyota

Kazuaki Hori

Takaya Maruyama

Takao Kihara

In an RFIC provided in a semiconductor device according to an embodiment, a low-noise amplifier () for reception and a power amplifier () for transmission are connected to a common antenna connection terminal (). Between the antenna connection terminal () and an LNA (), a circuit () is connected to be used for impedance matching, and a semiconductor switch (SW) is connected in parallel with the circuit ().

Semiconductor device

A radio frequency integrated circuit includes an amplification circuit for outputting a radio frequency signal to an antenna, a balun including a first terminal, a second terminal, a third terminal, and a fourth terminal, and a variable capacitance circuit including a fifth terminal and a sixth terminal. The first terminal and the second terminal of the balun receive output signals of the amplification circuit. The third terminal and the fourth terminal of the balun are connected to the fifth terminal and the sixth terminal of the variable capacitance circuit, respectively, and the fifth terminal is connected to a radio frequency output terminal. The variable capacitance circuit includes a plurality of capacity cells that are connected in parallel between two output terminals.

Digital variable capacitance circuit, resonant circuit, amplification circuit, and transmitter

A semiconductor apparatus, includes a common mode detector circuit that receives alternating current (AC) signals in a common mode.

Semiconductor apparatus and radio communication apparatus

In a related-art semiconductor device, there is a problem that a second-order harmonic distortion originating in a power amplifier driven by a rectangular-wave signal cannot be effectively suppressed. According to an embodiment, a semiconductor device generates a transmission signal RF_OUT for driving an antenna by receiving first transmission pulses INd_P and second transmission pulses INd_N having a duty ratio lower than 50%, adjusting a phase difference between the first and second transmission pulses INd_P and INd_N to a predefined phase difference, and supplying the phase-difference-adjusted first and second transmission pulses INd_P and INd_N to a power amplifier

In a semiconductor device, received signals of different frequency bands are input selectively to low noise amplifiers. A plurality of primary inductors are coupled between differential output nodes of the respective low noise amplifiers. A secondary inductor is provided commonly for the primary inductors, and magnetically coupled to the primary inductors. A demodulator converts a received signal transmitted from one of the primary inductors to the secondary inductor by electromagnetic induction, into a signal of a low frequency.

A semiconductor apparatus includes a common mode detector circuit that receives differential alternating current (AC) signal; and a detector circuit.

The present invention aims to provide a digital variable capacitance circuit, a resonant circuit, an amplification circuit, and a transmitter having a high performance. A digital variable capacitance circuitaccording to this embodiment is a digital variable capacitance circuit including a plurality of unit capacity cells-to-connected in parallel between two output terminals OUTP and OUTN, in which the unit capacity cellcomprises: a first capacitor Cuhaving one end connected to one output terminal OUTP; a second capacitor Cuthat is connected in series with the first capacitor Cubetween the two output terminals; and an NMOS transistor Mthat is connected in parallel with the second capacitor Cuand is controlled in accordance with a digital control signal.

A semiconductor apparatus that can detect the amplitude level of harmonics is provided. A semiconductor apparatus includes a common mode detector circuit that detects alternating current (AC) signals in a common mode, and a detector circuit that detects the amplitude level of an even-order harmonic output from the common mode detector circuit. The common mode detector circuit combines the AC signals being differential signals in common mode, thereby cancelling out odd-order harmonics to obtain direct current and even-order harmonics. The detector circuit detects the amplitude level of the even-order harmonics from a signal obtained by the common mode detection, and outputs the detected amplitude level.

A variable gain amplifier circuit includes output nodes, a plurality of amplifiers, and a detection circuit. The amplifiers are coupled in parallel with each other between the output nodes and a reference node and selectively assume an operating state in accordance with a control signal. The detection circuit outputs a detection signal according to the magnitude of an input signal to each amplifier. Each amplifier includes a first transistor, a second transistor, and a bias circuit. The first transistor receives, at its control electrode, the input signal or a signal proportional to the input signal. The second transistor is series-coupled to the first transistor between the first reference node and an output node. The bias circuit applies a DC voltage of a magnitude according to the detection signal to a control electrode of the second transistor.

A semiconductor device for transmitting-signal amplification which has a fine resolution, a high dynamic range, a small occupied area, and low power consumption, is realized. An input signal amplitude is reduced every one half by a ladder network, and a transconductance amplifier stage is arranged corresponding to each node of the ladder network. An output of the transconductance amplifier stage is coupled to an output signal line in common. According to a control word WC&#x3c;&#x3e;, the transconductance amplifier stage is enabled selectively, and the output current which appears in the output signal line is added.

Growing community of inventors

Tokyo, Japan

Masakazu Mizokami