Renesas Technology Corp.

Renesas Electronics Corporation

Ttp Com Limited

Ttpcom Limited

Epoch Microelectronics, Inc.

Hitachi, Ltd.

Ttpom Limited

Toshiya Uozumi

Satoru Yamamoto

Hirotaka Oosawa

Yasuyuki Kimura

Keisuke Ueda

Satoshi Tanaka

Masumi Kasahara

Noriyuki Kurakami

Jiro Shinbo

Hirotaka Osawa

Ryo Endo

Satoshi Arayashiki

Robert Astle Henshaw

Robert Astel Henshaw

Chihiro Arai

Aleksander Dec

Ken Suyama

Hirokazu Miyagawa

Akira Okasaka

Mitsunori Samata

Russell P Mohn

Kenichi Shibata

Jiro Shimbo

Ikuya Ono

To provide a DC-DC converter capable of reducing noise and a wireless communication device including the same, the DC-DC converter according to an embodiment includes a pulse signal generation unit generating a pulse signal, a voltage conversion unit that has a switch portion provided between an input terminal and an output terminal and on/off controlled by the pulse signal, and outputs an output voltage obtained by stepping down an input voltage supplied to the input terminal, from the output terminal, and a control circuit that controls a value of a current flowing through the switch portion in an on-state based on a value of the input voltage.

DC-DC converter and wireless communication device including the same

To reduce the influence of a spurious in a high-frequency signal processing device and a wireless communication system each provided with a digital type PLL circuit. In a digital type PLL circuit including a digital phase comparator unit, a digital low-pass filter, a digital control oscillator unit, and a multi-module driver unit (frequency divider unit), the clock frequency of a clock signal in the digital phase comparator unit is configured selectably among a plurality of options. The clock frequency is selected among frequencies which are integer multiples of a reference frequency, in accordance with which frequency band of a standard is to be set for an oscillation output signal of the digital control oscillator unit.

High-frequency signal processing device and wireless communication system

A semiconductor device includes a controlled oscillator and a control unit. The controlled oscillator includes a resonance circuit, an amplification unit, and a current adjustment unit. The resonance circuit includes one or a plurality of inductors and a first capacitive unit having a variable capacitance value. The amplification unit is connected to the resonance circuit, and outputs a local oscillation signal having an oscillation frequency corresponding to a resonance frequency of the resonance circuit. The current adjustment unit adjusts a value of a drive current to be supplied to the amplification unit. The control unit controls the capacitance value of the first capacitive unit and the current adjustment unit. When the control unit instructs the current adjustment unit to change the value of the drive current to be supplied to the amplification unit, the control unit also changes the capacitance value of the first capacitive unit.

Semiconductor device

A conventional semiconductor device has a problem that acquisition of variation information of circuit elements constructing the semiconductor device is not easy. According to an embodiment, a semiconductor device has a control circuit which makes an oscillation circuit operate by at least two operation current values, obtains first frequency information related to frequency of an output signal corresponding to a first operation current value and second frequency information related to frequency of an output signal corresponding to a second operation current value, and obtains manufacture variation information of a circuit element on the basis of the difference between the first and second frequency information.

Semiconductor device and variation information obtaining program

A high-frequency signal processing device having a frequency synthesizer (PLL: Phase Locked Loop) is provided. A control circuit measures oscillation frequencies obtained upon setting a bias current of an oscillation circuit to first and second bias setting values and acquires a frequency difference amount of the oscillation frequencies. The frequency difference amount may be acquired as difference amount of setting values of a coarse adjustment capacitance setting signal (CTRM) using, for example, an automatic frequency selector unit. The control circuit retains a relationship of a difference amount of bias setting values and a difference value of setting values of the CTRM and approximating the relationship to a linear function. Thereafter, the control circuit defines, upon switching the bias current during locking of the PLL, the CTRM based on the linear function and switches the CTRM together with the bias current.

High-frequency signal processing device

In an ADPLL composed of a digital circuit, a technique improving phase difference detection in a vicinity of a phase difference of 0 (zero) is provided. A feedback loop comprises a PFD comparing phases and frequencies of a reference signal and a feedback signal, a TDC converting an output of the PFD into a digital value, a DLF removing a high frequency noise component from an output of the TDC, a DCO controlled based on an output of the DLF and a DIV frequency-dividing an output the DCO and outputting the feedback signal. An offset value is added at any portion of the feedback loop, a phase of the feedback signal is controlled and a value other than 0 is inputted to the TDC even when the ADPLL is locked.

PLL circuit with improved phase difference detection

A high frequency signal processing device is capable of carrying out high-accuracy modulation by a PLL circuit. A digital loop is configured in addition to an analog loop having, for example, a phase frequency detector, a charge pump circuit, and a loop filter. A digital calibration circuit is provided which searches for the optimal code set to a capacitor bank upon frequency modulation. Upon the search for the optimal code, a calibration controller first sets a division ratio based on a center frequency to a divider and determines the value of a voltage control signal using the analog loop. Then, the loop filter holds the value of the voltage control signal therein, and a division ratio corresponding to a 'center frequency+modulated portion' is set to the divider, thereby operating the digital loop. The optimal code is obtained by a convergent value of the digital loop.

High frequency signal processing device

A PLL circuit of which low power consumption and miniaturization are satisfied at the same time is provided. A phase comparator of the PLL circuit includes a counter and a time-to-digital converter. The counter receives a reference clock signal and a low frequency clock signal obtained by dividing an output of a digital controlled oscillator, and a high frequency clock signal. The counter detects a phase difference between the reference clock signal and the low frequency clock signal by counting the clock number of the high frequency clock signal. The time-to-digital converter receives the reference clock signal and the low frequency clock signal. The time-to-digital converter detects the phase difference between the reference clock signal and the low frequency clock signal to the accuracy of a time period shorter than a cycle of the high frequency clock signal, after the output of counter reaches a predetermined range.

Phase-locked loop circuit and communication apparatus

A level converter level-converts an oscillation output signal of a reference frequency oscillator and supplies the level-converted signal to a phase comparator of a PLL/fractional synthesizer for controlling an oscillation frequency of an RF transmission voltage-controlled oscillator. The level converter includes a self-bias type voltage amplifier which amplifies a reference frequency signal of the reference frequency oscillator. The self-bias type voltage amplifier includes a coupling capacitor, an amplifying transistor, a load and a bias element and suppresses a variation in the level of each harmonic component even though an external power supply voltage varies.

Semiconductor integrated circuit device for communication

In a communication semiconductor integrated circuit device using offset PLL architectures and including an oscillator circuit and a frequency divider circuit generating an intermediate frequency signal, the oscillator circuit includes an oscillator, a programmable frequency divider which frequency-divides the oscillation signal in accordance with frequency division information, a phase comparator detecting a phase difference between an output signal of the programmable frequency divider and a reference signal, and a frequency control unit for outputting a signal indicative of the phase difference and controlling the oscillation frequency of the oscillator, wherein a frequency division ratio generator circuit generates an integer part I and a fraction part F/G based on band information concerning the use frequency band and mode information along with channel information and for producing the frequency division ratio information to thereby give it to the programmable frequency divider.

Communication semiconductor integrated circuit device and a wireless communication system

The present invention provides a semiconductor integrated circuit for communication (RF IC) operable in a mode for receiving a received signal subjected to phase modulation and amplitude modulation and a mode for receiving a received signal subjected only to phase modulation. In the semiconductor integrated circuit for communication, a frequency band of a loop filter in a PLL circuit is switched and set so as to become large in a reception mode and become small in a transmission mode.

Semiconductor integrated circuit for communication and terminal device for mobile communication

The invention provides a communication semiconductor integrated circuit (RF IC) that, when a transmission oscillator is incorporated into a semiconductor chip, secures the oscillation operation over a wide frequency range, prevents a deterioration of a transmission spectrum, and thereby enhances the accuracy of an oscillation frequency. The integrated circuit corrects a dispersion of the KV characteristic of the transmission oscillator by calibrating a current Icp of the charge pump inside the phase control loop. More in concrete, the integrated circuit measures a KV value Kv of the transmission oscillator, and calibrates the current Icp of the charge pump so that Kv&#xb7;Icp falls into a predetermined value.

Communication semiconductor integrated circuit device for use in a mobile communication device for correcting variations in the oscillation frequency of a transmission oscillator by calibrating a current of the charge pump

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Takasaki, Japan

Toshiya Uozumi