Abstract: A bias circuit comprises: a first circuit that comprises a first resistor and a decoupling capacitor; a bias voltage generation circuit that comprises a first transistor being connected to the first circuit; one or more switches; a first replica circuit comprising a second circuit and a second transistor, the second circuit comprising a second resistor and a capacitor, the second transistor being connected to the second circuit; a second replica circuit comprising a third transistor; a comparator that makes a comparison between a pseudo-bias voltage and a reference voltage; and a control circuit that controls the one or more switches on the basis of the comparison result to reduce the amount of the current flowing through the first transistor.

Abstract: A bias circuit comprises: a first circuit that comprises a first resistor and a decoupling capacitor; a bias voltage generation circuit that comprises a first transistor being connected to the first circuit; one or more switches; a first replica circuit comprising a second circuit and a second transistor, the second circuit comprising a second resistor and a capacitor, the second transistor being connected to the second circuit; a second replica circuit comprising a third transistor; a comparator that makes a comparison between a pseudo-bias voltage and a reference voltage; and a control circuit that controls the one or more switches on the basis of the comparison result to reduce the amount of the current flowing through the first transistor.

Abstract: A power amplifier includes an output terminal, capacitive element groups including capacitive elements, and amplifier groups including amplifiers. Capacitive elements of the capacitive element groups are disposed on a first circle whose center is located on the output terminal. Amplifiers of the amplifier groups corresponding to the capacitive elements of the capacitive element groups are disposed on a second circle, which is concentric with and larger than the first circle. Each of the capacitive elements of the capacitive element groups is connected to both the output terminal and the corresponding amplifier of the amplifiers of the amplifier groups.

Abstract: A power amplifier includes an output terminal, capacitive element groups including capacitive elements, and amplifier groups including amplifiers. Capacitive elements of the capacitive element groups are disposed on a first circle whose center is located on the output terminal. Amplifiers of the amplifier groups corresponding to the capacitive elements of the capacitive element groups are disposed on a second circle, which is concentric with and larger than the first circle. Each of the capacitive elements of the capacitive element groups is connected to both the output terminal and the corresponding amplifier of the amplifiers of the amplifier groups.

Abstract: A power amplification device includes: a first power-amplifier array including a plurality of first switching elements that constitute a class-D power amplifier for a higher bits; a second power-amplifier array including a plurality of second switching elements that constitute a class-D power amplifier for a lower bits; and a capacitor array including a plurality of capacitance elements. The second switching elements have a larger on-resistance than the first switching elements. The first power-amplifier array is arranged between the second power-amplifier array and the capacitor array.

Abstract: An SCPA includes a pad, capacitative elements, amplifiers on an IC chip. The capacitative elements are disposed on a first circle whose center is located on the pad. The amplifiers which correspond to the capacitative elements are disposed on a second circle which is a concentric circle larger than the first circle. The pad, each of the capacitative elements, and a corresponding one of the amplifiers are aligned in a line so that the length of wiring is the shortest.

Abstract: A transmitting apparatus and transmission method are capable of easily and correctly mixing an in-phase component and a quadrature-phase component in a quadrature modulator. A local signal with a duty ratio of 25% or smaller is generated without using frequency which is a multiple of frequency of the local signal. Without providing switches in series to the outputs of I and Q amplifiers, a duty ratio of 25% or less is obtained. for the local signal, and class-D unit amplifiers are operated such that one of the I amplifier and the Q amplifier is connected to the output side in any state regardless of whether an output power control signal is at an on-level or an off-level. In producing the 25% duty ratio, a local signal with a 50% duty ratio is converted so as to have a duty ratio of 25% by I and Q duty converters.

Abstract: A transmission apparatus includes a digital amplifier having a plurality of class-D amplifiers connected in parallel to each other, each of the class-D amplifiers including a logic circuit that processes input signals from two input terminals and outputs the input signals to one of two output terminals, according to a selection signal, and including capacitors connected in series to the two output terminals, respectively, a first selection circuit that outputs either an in-phase component or a quadrature component of a transmission signal to the digital amplifier depending on the selection signal, and a second selection circuit that outputs either an in-phase component carrier signal or a quadrature component carrier signal to the digital amplifier depending on the selection signal.

Abstract: A power amplification device includes: a first power-amplifier array including a plurality of first switching elements that constitute a class-D power amplifier for a higher bits; a second power-amplifier array including a plurality of second switching elements that constitute a class-D power amplifier for a lower bits; and a capacitor array including a plurality of capacitance elements. The second switching elements have a larger on-resistance than the first switching elements. The first power-amplifier array is arranged between the second power-amplifier array and the capacitor array.

Abstract: A transmission apparatus includes a digital amplifier having a plurality of class-D amplifiers connected in parallel to each other, each of the class-D amplifiers including a logic circuit that processes input signals from two input terminals and outputs the input signals to one of two output terminals, according to a selection signal, and including capacitors connected in series to the two output terminals, respectively, a first selection circuit that outputs either an in-phase component or a quadrature component of a transmission signal to the digital amplifier depending on the selection signal, and a second selection circuit that outputs either an in-phase component carrier signal or a quadrature component carrier signal to the digital amplifier depending on the selection signal.

Abstract: A transmitting apparatus and transmission method are capable of easily and correctly mixing an in-phase component and a quadrature-phase component in a quadrature modulator. A local signal with a duty ratio of 25% or smaller is generated without using frequency which is a multiple of frequency of the local signal. Without providing switches in series to the outputs of I and Q amplifiers, a duty ratio of 25% or less is obtained. for the local signal, and class-D unit amplifiers are operated such that one of the I amplifier and the Q amplifier is connected to the output side in any state regardless of whether an output power control signal is at an on-level or an off-level. In producing the 25% duty ratio, a local signal with a 50% duty ratio is converted so as to have a duty ratio of 25% by I and Q duty converters.

Abstract: An SCPA includes a pad, capacitative elements, amplifiers on an IC chip. The capacitative elements are disposed on a first circle whose center is located on the pad. The amplifiers which correspond to the capacitative elements are disposed on a second circle which is a concentric circle larger than the first circle. The pad, each of the capacitative elements, and a corresponding one of the amplifiers are aligned in a line so that the length of wiring is the shortest.