Abstract: Improvement in linearity is achieved at low costs in a power amplifier module employing an envelope tracking system. The power amplifier module includes a first power amplifier circuit that amplifies a radio frequency signal and that outputs a first amplified signal, a second power amplifier circuit that amplifies the first amplified signal on the basis of a source voltage varying depending on amplitude of the radio frequency signal and that outputs a second amplified signal, and a matching circuit that includes first and second capacitors connected in series between the first and second power amplifier circuit and an inductor connected between a node between the first and second capacitors and a ground and that decreases a gain of the first power amplifier circuit as the source voltage of the second power amplifier circuit increases.

Abstract: A transmission circuit includes a transmission signal generation unit, a control unit, and a transmission signal amplification unit. The transmission signal generation unit generates a transmission signal that has been modulated. The transmission signal amplification unit includes a power amplifier that amplifies the transmission signal. The control unit determines a supply voltage signal having an amplitude characteristic of a period identical to that of an envelope of the transmission signal and supplies the supply voltage signal to the power amplifier. The control unit determines an output timing of the supply voltage signal such that a phase difference between a phase of the envelope of the transmission signal and a phase of the supply voltage signal does not become zero.

Abstract: A power amplifier circuit includes first and second transistors and a first voltage output circuit. A radio frequency signal is input into a base of the first transistor. The first voltage output circuit outputs a first voltage in accordance with a power supply voltage. The first voltage is supplied to a base or a gate of the second transistor. An emitter or a source of the second transistor is connected to a collector of the first transistor. A first amplified signal generated by amplifying the radio frequency signal is output from a collector or a drain of the second transistor.

Abstract: Provided is a power amplification module that includes: a first transistor, a first signal being inputted to a base thereof; a second transistor, the first signal being inputted to a base thereof and a collector thereof being connected to a collector of the first transistor; a first resistor, a first bias current being supplied to one end thereof and another end thereof being connected to the base of the first transistor; a second resistor, one end thereof being connected to the one end of the first resistor and another end thereof being connected to the base of the second transistor; and a third resistor, a second bias current being supplied to one end thereof and another end thereof being connected to the base of the second transistor.

Abstract: Provided is a power amplification module that includes: a first transistor, a first signal being inputted to a base thereof; a second transistor, the first signal being inputted to a base thereof and a collector thereof being connected to a collector of the first transistor; a first resistor, a first bias current being supplied to one end thereof and another end thereof being connected to the base of the first transistor; a second resistor, one end thereof being connected to the one end of the first resistor and another end thereof being connected to the base of the second transistor; and a third resistor, a second bias current being supplied to one end thereof and another end thereof being connected to the base of the second transistor.

Abstract: A transmission circuit includes a transmission signal generation unit, a control unit, and a transmission signal amplification unit. The transmission signal generation unit generates a transmission signal that has been modulated. The transmission signal amplification unit includes a power amplifier that amplifies the transmission signal. The control unit determines a supply voltage signal having an amplitude characteristic of a period identical to that of an envelope of the transmission signal and supplies the supply voltage signal to the power amplifier. The control unit determines an output timing of the supply voltage signal such that a phase difference between a phase of the envelope of the transmission signal and a phase of the supply voltage signal does not become zero.

Abstract: Improvement in linearity is achieved at low costs in a power amplifier module employing an envelope tracking system. The power amplifier module includes a first power amplifier circuit that amplifies a radio frequency signal and that outputs a first amplified signal, a second power amplifier circuit that amplifies the first amplified signal on the basis of a source voltage varying depending on amplitude of the radio frequency signal and that outputs a second amplified signal, and a matching circuit that includes first and second capacitors connected in series between the first and second power amplifier circuit and an inductor connected between a node between the first and second capacitors and a ground and that decreases a gain of the first power amplifier circuit as the source voltage of the second power amplifier circuit increases.

Abstract: Improvement in linearity is achieved at low costs in a power amplifier module employing an envelope tracking system. The power amplifier module includes a first power amplifier circuit that amplifies a radio frequency signal and that outputs a first amplified signal, a second power amplifier circuit that amplifies the first amplified signal on the basis of a source voltage varying depending on amplitude of the radio frequency signal and that outputs a second amplified signal, and a matching circuit that includes first and second capacitors connected in series between the first and second power amplifier circuit and an inductor connected between a node between the first and second capacitors and a ground and that decreases a gain of the first power amplifier circuit as the source voltage of the second power amplifier circuit increases.

Abstract: Improvement in linearity is achieved at low costs in a power amplifier module employing an envelope tracking system. The power amplifier module includes a first power amplifier circuit that amplifies a radio frequency signal and that outputs a first amplified signal, a second power amplifier circuit that amplifies the first amplified signal on the basis of a source voltage varying depending on amplitude of the radio frequency signal and that outputs a second amplified signal, and a matching circuit that includes first and second capacitors connected in series between the first and second power amplifier circuit and an inductor connected between a node between the first and second capacitors and a ground and that decreases a gain of the first power amplifier circuit as the source voltage of the second power amplifier circuit increases.

Abstract: Provided is a power amplification module that includes: a first transistor, a first signal being inputted to a base thereof; a second transistor, the first signal being inputted to a base thereof and a collector thereof being connected to a collector of the first transistor; a first resistor, a first bias current being supplied to one end thereof and another end thereof being connected to the base of the first transistor; a second resistor, one end thereof being connected to the one end of the first resistor and another end thereof being connected to the base of the second transistor; and a third resistor, a second bias current being supplied to one end thereof and another end thereof being connected to the base of the second transistor.

Abstract: Improvement in linearity is achieved at low costs in a power amplifier module employing an envelope tracking system. The power amplifier module includes a first power amplifier circuit that amplifies a radio frequency signal and that outputs a first amplified signal, a second power amplifier circuit that amplifies the first amplified signal on the basis of a source voltage varying depending on amplitude of the radio frequency signal and that outputs a second amplified signal, and a matching circuit that includes first and second capacitors connected in series between the first and second power amplifier circuit and an inductor connected between a node between the first and second capacitors and a ground and that decreases a gain of the first power amplifier circuit as the source voltage of the second power amplifier circuit increases.

Abstract: Improvement in linearity is achieved at low costs in a power amplifier module employing an envelope tracking system. The power amplifier module includes a first power amplifier circuit that amplifies a radio frequency signal and that outputs a first amplified signal, a second power amplifier circuit that amplifies the first amplified signal on the basis of a source voltage varying depending on amplitude of the radio frequency signal and that outputs a second amplified signal, and a matching circuit that includes first and second capacitors connected in series between the first and second power amplifier circuit and an inductor connected between a node between the first and second capacitors and a ground and that decreases a gain of the first power amplifier circuit as the source voltage of the second power amplifier circuit increases.

Abstract: Variable operating currents are generated in relation to input signal power and output signal power and achieving both low noise and low power consumption. Emitter follower circuits are attached to output terminals of a frequency divider for generating a local signal. By adjusting the currents flowing through the emitter follower circuits, the amounts of currents flowing into mixers is adjusted. When the amounts of currents of local signals flowing into the mixers increases, the effect of noise suppression is expected. The amounts of the currents flowing through the emitter follower circuits is changed depending on the amplification factor of variable amplifiers.

Abstract: The invention provides a control method for generating variable operating currents in relation to input signal power and output signal power and achieving both low noise and low power consumption. Emitter follower circuits are attached to output terminals of a frequency divider for generating a local signal. By adjusting the currents flowing through the emitter follower circuits, the amount of currents flowing into mixers is adjusted. When the amount of currents of local signals flowing into the mixers increases, the effect of noise suppression is expected. The amount of the currents flowing through the emitter follower circuits is changed depending on the amplification factor of variable amplifiers.

Abstract: 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·Icp falls into a predetermined value.

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: 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: 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·Icp falls into a predetermined value.

Abstract: 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·Icp falls into a predetermined value.