Abstract: A transmission oscillator of differential output configuration is incorporated into a high frequency IC. Further, an equivalent impedance having an impedance equivalent to the impedance connected with a regular output terminal is provided. Or, a dummy external terminal for outputting transmit signals in opposite phase is provided. One of the differential outputs of the transmission oscillator is inputted to the power amplifier through the regular output terminal. The other of the differential outputs is connected to the equivalent impedance or the dummy external terminal.

Abstract: Disclosed is an apparatus for mobile communication system capable of constructing a system such as a mobile phone by setting a voltage corresponding to the characteristic variation of a PA even when a PA having characteristic variation is used. The mobile phone is the one employing the polar loop method, which comprises an antenna (1) for transmission and reception of signal waves; an antenna switch (2) for switching the transmission mode and the reception mode; a BBLSI (3) having a function to control the transmission and reception; an RFIC (4) having a function for modulating and demodulating the transmitted and received signals; and a PA (5) for amplifying up to the target output power by means of the amplitude modulation at the time of the transmission, wherein a bias voltage corresponding to the characteristic variation of the PA is set and supplied by a BIASDAC (6) formed of a register and a DAC so as to achieve the target output power at the time of the amplitude modulation in the PA.

Abstract: The dynamic range is changed by switching a current applied to an amplifying circuit to obtain the minimum ICP required to keep linearity with the number of multiplexes even when the number of multiplexes of data is changed by switching the operation current of the amplifying circuits of the transmission system and also supplying the information about number of multiplexes of data to be transmitted to the amplifying circuits of the transmission system from the baseband circuit. Thereby, the signal can be transmitted without distortion even when the number of multiplexes increases and the current of the amplifying circuit may be reduced when the number of multiplexes is small in order to reduce the current consumption in the communication semiconductor integrated circuit device which can form a wireless communication system of the code division multiplex system such as W-CDMA system.

Abstract: If a transmission oscillator is incorporated into a communication semiconductor integrated circuit, such as high a frequency IC, constituting a wireless communication system, a problem arises. The accuracy of control of the output power of a power amplifier is degraded. This degradation in accuracy is caused by coupling noise between the output pins of the transmission oscillator and an input pin for detection signals (feedback signals) associated with the output level of the power amplifier or crosstalk. To prevent this, a transmission oscillator of differential output configuration is incorporated into a high frequency IC and an impedance equivalent to the impedance connected with a regular output terminal or a dummy external terminal for outputting transmit signals in opposite phase is provided.

Abstract: The dynamic range is changed by switching a current applied to an amplifying circuit to obtain the minimum ICP required to keep linearity with the number of multiplexes even when the number of multiplexes of data is changed by switching the operation current of the amplifying circuits of the transmission system and also supplying the information about number of multiplexes of data to be transmitted to the amplifying circuits of the transmission system from the baseband circuit. Thereby, the signal can be transmitted without distortion even when the number of multiplexes increases and the current of the amplifying circuit may be reduced when the number of multiplexes is small in order to reduce the current consumption in the communication semiconductor integrated circuit device which can form a wireless communication system of the code division multiplex system such as W-CDMA system.

Abstract: A transmitter adopting a polar loop system including a phase control loop for controlling the phase of a carrier signal outputted from a transmitting oscillator and an amplitude control loop for controlling the amplitude of a transmitting output signal outputted from a power amplification circuit, and designed to be capable of performing transmission using a GMSK modulation mode and transmission using an 8-PSK modulation mode. In the transmitter, the phase control loop is shared as a phase control loop for use in the GMSK modulation mode and a phase control loop for use in the 8-PSK modulation mode. A component similar to any one of components constituting a loop filter is provided in parallel therewith so that the component can be connected or disconnected in accordance with the modulation mode, for example, by use of a switching element.

Abstract: A mobile communication system has a mobile phone in which a voltage is set corresponding to the characteristic variation of a PA even when a PA having characteristic variation is used. The mobile phone employs a polar loop method, which comprises an antenna (1) for transmission and reception of signal waves; an antenna switch (2) for switching the transmission mode and the reception mode; a BBLSI (3) having a function to control the transmission and reception; an RFIC (4) having a function for modulating and demodulating the transmitted and received signals; and a PA (5) for amplifying up to the target output power by means of the amplitude modulation at the time of the transmission.

Abstract: A transmitter adopting a polar loop system including a phase control loop for controlling the phase of a carrier signal outputted from a transmitting oscillator and an amplitude control loop for controlling the amplitude of a transmitting output signal outputted from a power amplification circuit, and designed to be capable of performing transmission using a GMSK modulation mode and transmission using an 8-PSK modulation mode. In the transmitter, the phase control loop is shared as a phase control loop for use in the GMSK modulation mode and a phase control loop for use in the 8-PSK modulation mode. A component similar to any one of components constituting a loop filter is provided in parallel therewith so that the component can be connected or disconnected in accordance with the modulation mode, for example, by use of a switching element.

Abstract: A variable gain amplifier of low amplitude distortion, and low noise, having a large variable range, is provided. A variable gain differential amplifier that controls a gain by use of bias current is used as each of unit amplifiers (VGAs) making up the variable gain amplifier. A large variable gain range is obtained by series-connecting a plurality of the variable gain differential amplifiers. An attenuator is installed on the input side of the unit amplifier (VGA) at least in the initial stage. By doing so, it becomes possible to prevent amplitude distortion from occurring to the respective VGAs. An attenuator utilizing voltage division by capacitors, generating no noise, is used for lowering noise. Further, the variable gain amplifier is provided with a fixed gain amplifier installed in the final stage as necessary in order to obtain a total gain as desired.

Abstract: A variable gain amplifier of low amplitude distortion, and low noise, having a large variable range, is provided. A variable gain differential amplifier that controls a gain by use of bias current is used as each of unit amplifiers (VGAs) making up the variable gain amplifier. A large variable gain range is obtained by series-connecting a plurality of the variable gain differential amplifiers. An attenuator is installed on the input side of the unit amplifier (VGA) at least in the initial stage. By doing so, it becomes possible to prevent amplitude distortion from occurring to the respective VGAs. An attenuator utilizing voltage division by capacitors, generating no noise, is used for lowering noise. Further, the variable gain amplifier is provided with a fixed gain amplifier installed in the final stage as necessary in order to obtain a total gain as desired.

Abstract: In a radio communication system having a phase control loop for phase modulation and an amplitude control loop for amplitude modulation and being capable of time divisional transmission and reception under a predetermined time management, when transmission in a first mode is switched to transmission in a second mode or when transmission in the second mode is switched to transmission in the first mode, the output level of the power amplifier is lowered once to a predetermined level higher than the level when transmission related circuits are activated, and thereafter the output level of the power amplifier is again ramped after the settings have been changed but without starting of a transmission oscillator, establishing of the phase control loop and the amplitude control loop.

Abstract: If a transmission oscillator is incorporated into a communication semiconductor integrated circuit, such as high a frequency IC, constituting a wireless communication system, a problem arises. The accuracy of control of the output power of a power amplifier is degraded. This degradation in accuracy is caused by coupling noise between the output pins of the transmission oscillator and an input pin for detection signals (feedback signals) associated with the output level of the power amplifier or crosstalk. To prevent this, a transmission oscillator of differential output configuration is incorporated into a high frequency IC and an impedance equivalent to the impedance connected with a regular output terminal or a dummy external terminal for outputting transmit signals in opposite phase is provided.

Abstract: When a transmitting oscillator is built in a communication semiconductor integrated circuit device like a high-frequency IC constituting a wireless communication system, the system prevents degradation of the accuracy of control on the output power of a power amplifier due to noise jumped from an output pin of the transmitting oscillator to an input pin for a detected signal (feedback signal) of an output level of the power amplifier. The transmitting oscillator is built in the high-frequency IC. The detected signal of the output level of the power amplifier, which is detected by a coupler, is attenuated to a level slightly higher than the level of noise jumped from the output pin of the transmitting oscillator to the input pin for a feedback signal of an amplitude control loop, which in turn is inputted to the feedback signal input pin of the high-frequency IC.

Abstract: The present invention provides a communication semiconductor integrated circuit device equipped with a high-frequency power amplifier circuit including a gain control amplifier and a bias circuit which supplies such a bias current as to linearly change the gain of the gain control amplifier, and a wireless communication system using the same. A bias current generating circuit which supplies a bias current to a linear amplifier that constitutes the communication high-frequency power amplifier circuit, comprises a plurality of variable current sources respectively different in current value and start level. These variable current sources are controlled according to an input control voltage and thereby combine their currents into a bias current. The combined bias current changes exponentially with respect to the input control voltage.

Abstract: Disclosed is an apparatus for mobile communication system capable of constructing a system such as a mobile phone by setting a voltage corresponding to the characteristic variation of a PA even when a PA having characteristic variation is used. The mobile phone is the one employing the polar loop method, which comprises an antenna (1) for transmission and reception of signal waves; an antenna switch (2) for switching the transmission mode and the reception mode; a BBLSI (3) having a function to control the transmission and reception; an RFIC (4) having a function for modulating and demodulating the transmitted and received signals; and a PA (5) for amplifying up to the target output power by means of the amplitude modulation at the time of the transmission, wherein a bias voltage corresponding to the characteristic variation of the PA is set and supplied by a BIASDAC (6) formed of a register and a DAC so as to achieve the target output power at the time of the amplitude modulation in the PA.

Abstract: The present invention provides a communication semiconductor integrated circuit device equipped with a high-frequency power amplifier circuit including a gain control amplifier and a bias circuit which supplies such a bias current as to linearly change the gain of the gain control amplifier, and a wireless communication system using the same. A bias current generating circuit which supplies a bias current to a linear amplifier that constitutes the communication high-frequency power amplifier circuit, comprises a plurality of variable current sources respectively different in current value and start level. These variable current sources are controlled according to an input control voltage and thereby combine their currents into a bias current. The combined bias current changes exponentially with respect to the input control voltage.

Abstract: The dynamic range is changed by switching a current applied to an amplifying circuit to obtain the minimum ICP required to keep linearity with the number of multiplexes even when the number of multiplexes of data is changed by switching the operation current of the amplifying circuits of the transmission system and also supplying the information about number of multiplexes of data to be transmitted to the amplifying circuits of the transmission system from the baseband circuit. Thereby, the signal can be transmitted without distortion even when the number of multiplexes increases and the current of the amplifying circuit may be reduced when the number of multiplexes is small in order to reduce the current consumption in the communication semiconductor integrated circuit device which can form a wireless communication system of the code division multiplex system such as W-CDMA system.

Abstract: A variable gain amplifier of low amplitude distortion, and low noise, having a large variable range, is provided. A variable gain differential amplifier that controls a gain by use of bias current is used as each of unit amplifiers (VGAs) making up the variable gain amplifier. A large variable gain range is obtained by series-connecting a plurality of the variable gain differential amplifiers. An attenuator is installed on the input side of the unit amplifier (VGA) at least in the initial stage. By doing so, it becomes possible to prevent amplitude distortion from occurring to the respective VGAs. An attenuator utilizing voltage division by capacitors, generating no noise, is used for lowering noise. Further, the variable gain amplifier is provided with a fixed gain amplifier installed in the final stage as necessary in order to obtain a total gain as desired.

Abstract: As the gain control amplifiers for amplifying the reception signal, the step amplifiers are used. Two sets of these step amplifiers are provided and are then controlled to be used alternately. When switching of the gain occurs, after the gain is switched with the step amplifier not operated and offset is cancelled, the amplifier to which the reception signal is inputted is switched. Accordingly, the step amplifier can be used as the gain control amplifier for amplifying the reception signal to provide almost constant power consumption even when the gain is changed depending on the intensity of reception signal in the semiconductor integrated circuit device for communication to form a wireless communication system of dual-mode or more modes including the W-CDMA system. As a result, the operation life of battery, namely, the reception waiting period and communication period by single charging process can be expanded.

Abstract: A polar loop based radio telecommunication apparatus which has a phase control loop for controlling the phase of a carrier outputted from an oscillator for transmitter, and an amplitude control loop for controlling the amplitude of a transmission output signal outputted from a power amplifier circuit, wherein precharge means is provided on a forward path from a current source, through the power amplifier circuit, to a detection circuit, forming the amplitude control loop, for rapidly increasing a control voltage for the power amplifier circuit to a power threshold upon starting transmission.