A transistor circuit includes a transistor having a gate terminal and first and second conduction terminals, a first circuit configured to convert an AC input signal of the transistor circuit to a gate bias voltage and to apply the gate bias voltage to the gate terminal of the transistor, a second circuit configured to convert the AC input signal of the transistor circuit to a control voltage, and a switching circuit configured to apply a first voltage to the first conduction terminal of the transistor in response to the control voltage.

An amplifying circuit includes a first reconfigurable amplifier configured to selectively operate in a cascode mode or a non-cascode mode, wherein an input of the first reconfigurable amplifier is coupled to a first input of the amplifying circuit, and an output of the first reconfigurable amplifier is coupled to an output of the amplifying circuit. The amplifying circuit also includes a second reconfigurable amplifier configured to selectively operate in the cascode mode or the non-cascode mode, wherein an input of the second reconfigurable amplifier is coupled to a second input of the amplifying circuit, and an output of the second reconfigurable amplifier is coupled to the output of the amplifying circuit.

An integrated circuit arrangement for a microphone, a microphone system and a method for adjusting circuit parameters of the microphone are disclosed. In an embodiment an integrated circuit includes an amplifier circuit with a first switchable network circuit for adjusting an amplifier current of the amplifier circuit, the first switchable network circuit comprising a plurality of switches (SW1, . . . , SWx) each coupled with a first control port of the first switchable network circuit and a control unit coupled with the first control port of the first switchable network circuit and configured to control a setting of the respective switches (SW1, . . . , SWx) of the first switchable network circuit.

A communications device includes a transmission chain coupled to an antenna a receiver chain coupled to the antenna. The receiver chain includes an amplifier device having an input coupled to the antenna. A controlled switching circuit is included in the amplifier device and is operable to selectively disconnect conduction terminals of an amplifying transistor from power supply terminals when the transmission chain is operating to pass a transmit signal to the antenna.

An amplifying circuit includes a first reconfigurable amplifier configured to selectively operate in a cascode mode or a non-cascode mode, wherein an input of the first reconfigurable amplifier is coupled to a first input of the amplifying circuit, and an output of the first reconfigurable amplifier is coupled to an output of the amplifying circuit. The amplifying circuit also includes a second reconfigurable amplifier configured to selectively operate in the cascode mode or the non-cascode mode, wherein an input of the second reconfigurable amplifier is coupled to a second input of the amplifying circuit, and an output of the second reconfigurable amplifier is coupled to the output of the amplifying circuit.

A transistor circuit includes a transistor having a gate terminal and first and second conduction terminals, a first circuit configured to convert an AC input signal of the transistor circuit to a gate bias voltage and to apply the gate bias voltage to the gate terminal of the transistor, a second circuit configured to convert the AC input signal of the transistor circuit to a control voltage, and a switching circuit configured to apply a first voltage to the first conduction terminal of the transistor in response to the control voltage.

An integrated circuit arrangement for a microphone, a microphone system and a method for adjusting circuit parameters of the microphone are disclosed. In an embodiment an integrated circuit includes an amplifier circuit with a first switchable network circuit for adjusting an amplifier current of the amplifier circuit, the first switchable network circuit comprising a plurality of switches (SW1, . . . ,SWx) each coupled with a first control port of the first switchable network circuit and a control unit coupled with the first control port of the first switchable network circuit and configured to control a setting of the respective switches (SW1, . . . ,SWx) of the first switchable network circuit.

A conversion circuit is disclosed. In one aspect, the conversion circuit includes a first input terminal for receiving a digital signal. The conversion circuit includes a second input terminal for receiving a bias voltage signal. The conversion circuit includes an output terminal for outputting a current. The conversion circuit includes a first and a second switch transistor connected to the first input terminal for receiving the digital signal. The conversion circuit includes a first and a second current source transistor connected to the second input terminal for receiving the bias voltage signal. The conversion circuit further includes a first branch, wherein the first switch transistor is connected to the output terminal via the first current source transistor. The conversion circuit further includes a second branch, wherein the second current source transistor is connected to the output terminal via the second switch transistor.

A distributed amplifier includes: an input-side transmission line; M amplification circuits; M output-side transmission lines; and a combination circuit configured to combine outputs of the M output-side transmission lines; wherein the input-side transmission line has an input-side serial line formed by connecting in series MN unit transmission lines each including the same line length, and an input-side terminating resistor, the M amplification circuits each includes N amplifiers and the N amplifiers of the i-th amplification circuit take the input node of the ((k1) M+i)-th input-side transmission line to be the input, and the output-side transmission line includes an output-side serial line including N transmission lines each being connected in series between the neighboring outputs of the N amplifiers and each having a line width in which the phase of the output of the amplifier in each stage agrees with one another.

A conversion circuit is disclosed. In one aspect, the conversion circuit includes a first input terminal for receiving a digital signal. The conversion circuit includes a second input terminal for receiving a bias voltage signal. The conversion circuit includes an output terminal for outputting a current. The conversion circuit includes a first and a second switch transistor connected to the first input terminal for receiving the digital signal. The conversion circuit includes a first and a second current source transistor connected to the second input terminal for receiving the bias voltage signal. The conversion circuit further includes a first branch, wherein the first switch transistor is connected to the output terminal via the first current source transistor. The conversion circuit further includes a second branch, wherein the second current source transistor is connected to the output terminal via the second switch transistor.