Abstract: 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.

Abstract: An RF IC in which a PLL circuit including a loop filter is incorporated into a semiconductor chip is achieved without increasing power consumption or chip size. The RF IC includes a VCO capable of switching oscillation frequency bands, a variable frequency divider, a phase comparator, and a loop filter, which are contained in the PLL loop. A discrimination circuit discriminates a lead or lag in a phase of an output signal from the variable frequency divider against a reference signal and an automatic band selecting circuit generates a signal for switching the frequency bands of the VCO based on output from the discrimination circuit. While switching the frequency bands of the VCO by means of bisection algorithm, the RF IC detects an optimum frequency band, and adds offset to it to determine a final usable frequency band.

Abstract: An RF IC in which a PLL circuit including a loop filter is incorporated into a semiconductor chip is achieved without increasing power consumption or chip size. The RF IC includes a VCO capable of switching oscillation frequency bands, a variable frequency divider, a phase comparator, and a loop filter, which are contained in the PLL loop. A discrimination circuit discriminates a lead or lag in a phase of an output signal from the variable frequency divider against a reference signal and an automatic band selecting circuit generates a signal for switching the frequency bands of the VCO based on output from the discrimination circuit. While switching the frequency bands of the VCO by means of bisection algorithm, the RF IC detects an optimum frequency band, and adds offset to it to determine a final usable frequency band.

Abstract: In a PLL circuit including an oscillator, a phase comparator, a charge pump circuit, and a loop filter, without providing a plurality of capacitative elements, that is, without increasing the occupied area so much, the characteristics of the PLL circuit can be adjusted according to manufacture variations in a resistive element and a capacitative element, and a loop filter can be formed on a chip. A resistive element and a capacitative element of a loop filter are formed on a semiconductor chip. As the resistive element, a plurality of elements having different resistance values are provided and switched by a switch, thereby enabling the resistance value to be adjusted. Current in a charge pump circuit is also made adjustable, and the current of the charge pump circuit is adjusted according to switching among the resistance values of the resistive elements.

Abstract: In a PLL circuit including an oscillator, a phase comparator, a charge pump circuit, and a loop filter, without providing a plurality of capacitative elements, that is, without increasing the occupied area so much, the characteristics of the PLL circuit can be adjusted according to manufacture variations in a resistive element and a capacitative element, and a loop filter can be formed on a chip. A resistive element and a capacitative element of a loop filter are formed on a semiconductor chip. As the resistive element, a plurality of elements having different resistance values are provided and switched by a switch, thereby enabling the resistance value to be adjusted. Current in a charge pump circuit is also made adjustable, and the current of the charge pump circuit is adjusted according to switching among the resistance values of the resistive elements.

Abstract: A communication semiconductor integrated circuit has an oscillator circuit forming part of a transmission PLL circuit fabricated on a single semiconductor chip together with an oscillator circuit forming part of a reception PLL circuit and an oscillator circuit for an intermediate frequency. The oscillator circuit forming part of the transmission PLL circuit is configured to be operable in a plurality of bands. A circuit for measuring the oscillating frequency of the oscillator circuit forming part of the transmission PLL circuit is also used for measuring the oscillating frequency of the oscillator circuit forming part of the reception PLL circuit or for measuring the oscillating frequency of the oscillator circuit for the intermediate frequency.

Abstract: In a PLL circuit including an oscillator, a phase comparator, a charge pump circuit, and a loop filter, without providing a plurality of capacitative elements, that is, without increasing the occupied area so much, the characteristics of the PLL circuit can be adjusted according to manufacture variations in a resistive element and a capacitative element, and a loop filter can be formed on a chip. A resistive element and a capacitative element of a loop filter are formed on a semiconductor chip. As the resistive element, a plurality of elements having different resistance values are provided and switched by a switch, thereby enabling the resistance value to be adjusted. Current in a charge pump circuit is also made adjustable, and the current of the charge pump circuit is adjusted according to switching among the resistance values of the resistive elements.

Abstract: A communication semiconductor integrated circuit device includes an RFVCO and a TXVCO and is formed over one semiconductor substrate, and has a first operation mode (idle mode) which does not perform transmission and reception, a second operation mode (warmup mode) which performs a preparation prior to the start of transmission or reception, and a third operation mode (transmission or reception mode) which performs transmission or reception. In the first operation mode, two oscillators are deactivated, and the operation of selecting a frequency band to be used in at least the TXVCO which generates a transmit signal, is performed in the second operation mode.

Abstract: An RF IC in which a PLL circuit including a loop filter is incorporated into a semiconductor chip is achieved without increasing power consumption or chip size. The RF IC includes a VCO capable of switching oscillation frequency bands, a variable frequency divider, a phase comparator, and a loop filter, which are contained in the PLL loop. A discrimination circuit discriminates a lead or lag in a phase of an output signal from the variable frequency divider against a reference signal and an automatic band selecting circuit generates a signal for switching the frequency bands of the VCO based on output from the discrimination circuit. While switching the frequency bands of the VCO by means of bisection algorithm, the RF IC detects an optimum frequency band, and adds offset to it to determine a final usable frequency band.

Abstract: A semiconductor integrated circuit device has an oscillation circuit using either an oscillator or an oscillation module, as an external part of a reference oscillation circuit. Two external terminals are provided in correspondence with the oscillation circuit. A control terminal (base terminal) of a transistor of the oscillation circuit is connected to one external terminal, and part of an output of the transistor is fed back to the control terminal. The other external terminal is connected to a power source voltage terminal via a resistive element of a high resistance value. Capacitor elements are connected between the two external terminals. When an oscillator is connected to the one of the external terminals, the other external terminal is fixed to a constant potential. When an electronic part for oscillation (oscillation module) is connected, the other external terminal is set into an open state.

Abstract: An RF IC in which a PLL circuit including a loop filter is incorporated into a semiconductor chip is achieved without increasing power consumption or chip size. The RF IC includes a VCO capable of switching oscillation frequency bands, a variable frequency divider, a phase comparator, and a loop filter, which are contained in the PLL loop. A discrimination circuit discriminates a lead or lag in a phase of an output signal from the variable frequency divider against a reference signal and an automatic band selecting circuit generates a signal for switching the frequency bands of the VCO based on output from the discrimination circuit. While switching the frequency bands of the VCO by means of bisection algorithm, the RF IC detects an optimum frequency band, and adds offset to it to determine a final usable frequency band.

Abstract: 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.

Abstract: A communication semiconductor integrated circuit has an oscillator circuit forming part of a transmission PLL circuit fabricated on a single semiconductor chip together with an oscillator circuit forming part of a reception PLL circuit and an oscillator circuit for an intermediate frequency. The oscillator circuit for the transmission PLL circuit is configured to be operable in a plurality of bands. The communication semiconductor integrated circuit also comprises a circuit for measuring the oscillating frequency of the oscillator circuit for the transmission PLL circuit, and a storage circuit for storing the result of measurement made by the measuring circuit. A band to be used by the oscillator circuit for the transmission PLL circuit is determined based on values for setting the oscillating frequencies of the oscillator circuit forming part of the reception PLL circuit and the intermediate frequency oscillator circuit, and the result of measurement stored in the storage circuit.

Abstract: In a PLL circuit including an oscillator, a phase comparator, a charge pump circuit, and a loop filter, without providing a plurality of capacitative elements, that is, without increasing the occupied area so much, the characteristics of the PLL circuit can be adjusted according to manufacture variations in a resistive element and a capacitative element, and a loop filter can be formed on a chip. A resistive element and a capacitative element of a loop filter are formed on a semiconductor chip. As the resistive element, a plurality of elements having different resistance values are provided and switched by a switch, thereby enabling the resistance value to be adjusted. Current in a charge pump circuit is also made adjustable, and the current of the charge pump circuit is adjusted according to switching among the resistance values of the resistive elements.

Abstract: A communication semiconductor integrated circuit has an oscillator circuit forming part of a transmission PLL circuit fabricated on a single semiconductor chip together with an oscillator circuit forming part of a reception PLL circuit and an oscillator circuit for an intermediate frequency. The oscillator circuit forming part of the transmission PLL circuit is configured to be operable in a plurality of bands. A circuit for measuring the oscillating frequency of the oscillator circuit forming part of the transmission PLL circuit is also used for measuring the oscillating frequency of the oscillator circuit forming part of the reception PLL circuit or for measuring the oscillating frequency of the oscillator circuit for the intermediate frequency.

Abstract: A communication semiconductor integrated circuit device includes an RFVCO and a TXVCO and is formed over one semiconductor substrate, and has a first operation mode (idle mode) which does not perform transmission and reception, a second operation mode (warmup mode) which performs a preparation prior to the start of transmission or reception, and a third operation mode (transmission or reception mode) which performs transmission or reception. In the first operation mode, two oscillators are deactivated, and the operation of selecting a frequency band to be used in at least the TXVCO which generates a transmit signal, is performed in the second operation mode.

Abstract: A communication semiconductor integrated circuit has an oscillator circuit forming part of a transmission PLL circuit fabricated on a single semiconductor chip together with an oscillator circuit forming part of a reception PLL circuit and an oscillator circuit for an intermediate frequency. The oscillator circuit forming part of the transmission PLL circuit is configured to be operable in a plurality of bands. A circuit for measuring the oscillating frequency of the oscillator circuit forming part of the transmission PLL circuit is also used for measuring the oscillating frequency of the oscillator circuit forming part of the reception PLL circuit or for measuring the oscillating frequency of the oscillator circuit for the intermediate frequency.

Abstract: An RF IC in which a PLL circuit including a loop filter is incorporated into a semiconductor chip is achieved without increasing power consumption or chip size. The RF IC includes a VCO capable of switching oscillation frequency bands, a variable frequency divider, a phase comparator, and a loop filter, which are contained in the PLL loop. A discrimination circuit discriminates a lead or lag in a phase of an output signal from the variable frequency divider against a reference signal and an automatic band selecting circuit generates a signal for switching the frequency bands of the VCO based on output from the discrimination circuit. While switching the frequency bands of the VCO by means of bisection algorithm, the RF IC detects an optimum frequency band, and adds offset to it to determine a final usable frequency band.

Abstract: The invention provides a semiconductor integrated circuit device having therein an oscillation circuit using either an oscillator or an oscillation module, which can be freely selected by the user, as an external part of a reference oscillation circuit without increasing the number of external parts and the number of external terminals. Two external terminals are provided in correspondence with an oscillation circuit. A control terminal (base terminal) of a transistor as a component of the oscillation circuit is connected to the one external terminal as one of the external terminals, and a path for feeding back a part of an output of the transistor to the control terminal is provided so that the oscillation circuit can oscillate. The other external terminal is connected to a power source voltage terminal via a resistive element of a high resistance value. Capacitor elements are connected between the two external terminals.

Abstract: A communication semiconductor integrated circuit has an oscillator circuit forming part of a transmission PLL circuit fabricated on a single semiconductor chip together with an oscillator circuit forming part of a reception PLL circuit and an oscillator circuit for an intermediate frequency. The oscillator circuit for the transmission PLL circuit is configured to be operable in a plurality of bands. The communication semiconductor integrated circuit also comprises a circuit for measuring the oscillating frequency of the oscillator circuit for the transmission PLL circuit, and a storage circuit for storing the result of measurement made by the measuring circuit. A band to be used by the oscillator circuit for the transmission PLL circuit is determined based on values for setting the oscillating frequencies of the oscillator circuit forming part of the reception PLL circuit and the intermediate frequency oscillator circuit, and the result of measurement stored in the storage circuit.