Abstract: An apparatus that generates and limits a bias current of a power amplifier is provided. The apparatus includes a bias current circuit that generates a bias current to bias the power amplifier, and critically limit an increase in bias current, and a band gap reference circuit that provides a reference voltage or a reference current to the bias current circuit. The bias current circuit is configured to critically limit the increase in bias current, as a first bias transistor that generates the bias current is converted from a triode region to a saturation region, based on the reference voltage or the reference current.

Abstract: An apparatus that generates and limits a bias current of a power amplifier is provided. The apparatus includes a bias current circuit that generates a bias current to bias the power amplifier, and critically limit an increase in bias current, and a band gap reference circuit that provides a reference voltage or a reference current to the bias current circuit. The bias current circuit is configured to critically limit the increase in bias current, as a first bias transistor that generates the bias current is converted from a triode region to a saturation region, based on the reference voltage or the reference current.

Abstract: A bias timing control circuit includes a current source, a bias switch circuit, a duty cycle sensing circuit, and a switching control circuit. The bias switch circuit includes a first path switch, connected between an output node of the current source and a bias amplifying circuit, and a second path switch, connected between the output node of the current source and a temperature compensation circuit. The duty cycle sensing circuit is configured to generate a timing control signal based on a duty cycle of a transmission enable signal. The switching control circuit is configured to control a first turn-on time of the first path switch during an initial startup period, and a second turn-on time of the second path switch during a normal driving period subsequent to the initial startup period to adjust a warm-up time of a power amplifying circuit based on the timing control signal.

Abstract: An amplifying apparatus is provided. The amplifying apparatus comprises an amplifying circuit comprising a power amplifier and a bias circuit, the bias circuit is configured to detect an ambient temperature of the power amplifier to output a temperature voltage and regulate an internal current based on an input control signal to supply a bias current obtained by the regulation to the power amplifier; and a temperature control circuit that generates the control signal based on the temperature voltage during initial driving from a transmission mode starting point in time to an input point in time at which an input signal is input and outputting the control signal to the amplifying circuit.

Abstract: A bias circuit includes a current source to generate a reference current, a temperature compensation portion in an off-state in an initial start period in response to a first control signal, and in an on-state in a normal driving period, subsequent to the initial start period, and to receive a first current of the reference current, and a bias output portion to generate a warm up current based on the reference current in the initial start period and to generate a bias current based on a second current, which is lower than the reference current by an amount of the first current, in the normal driving period.

Abstract: A bias timing control circuit includes a current source, a bias switch circuit, a duty cycle sensing circuit, and a switching control circuit. The bias switch circuit includes a first path switch, connected between an output node of the current source and a bias amplifying circuit, and a second path switch, connected between the output node of the current source and a temperature compensation circuit. The duty cycle sensing circuit is configured to generate a timing control signal based on a duty cycle of a transmission enable signal. The switching control circuit is configured to control a first turn-on time of the first path switch during an initial startup period, and a second turn-on time of the second path switch during a normal driving period subsequent to the initial startup period to adjust a warm-up time of a power amplifying circuit based on the timing control signal.

Abstract: An amplifying apparatus is provided. The amplifying apparatus comprises an amplifying circuit comprising a power amplifier and a bias circuit, the bias circuit is configured to detect an ambient temperature of the power amplifier to output a temperature voltage and regulate an internal current based on an input control signal to supply a bias current obtained by the regulation to the power amplifier; and a temperature control circuit that generates the control signal based on the temperature voltage during initial driving from a transmission mode starting point in time to an input point in time at which an input signal is input and outputting the control signal to the amplifying circuit.

Abstract: A bias circuit includes a current source to generate a reference current, a temperature compensation portion in an off-state in an initial start period in response to a first control signal, and in an on-state in a normal driving period, subsequent to the initial start period, and to receive a first current of the reference current, and a bias output portion to generate a warm up current based on the reference current in the initial start period and to generate a bias current based on a second current, which is lower than the reference current by an amount of the first current, in the normal driving period.

Abstract: A radio frequency switch apparatus includes a radio frequency switch, a dynamic bias circuit, and a switch control circuit. The radio frequency switch includes a first radio frequency switch circuit connected between a first signal terminal and an input terminal. The first radio frequency switch circuit includes a series switch and a shunt switch. The dynamic bias circuit is configured to generate a bias voltage and a buffer voltage lower than a battery voltage by a preset voltage, using the battery voltage and configured to output the bias voltage to a signal line connected to the input terminal. The switch control circuit is configured to generate first and second gate voltages to switch the first radio frequency switch circuit, based on a band selection signal, using the battery voltage and the buffer voltage.

Abstract: A band selection switch apparatus includes: a first switch including a first series switch disposed between a transmission input terminal and a first transmission and reception terminal; a second switch including a second series switch disposed between the transmission input terminal and a first transmission terminal; and a third switch including a third series switch disposed between a first reception output terminal and the first transmission and reception terminal. The first series switch includes a first series switch circuit including first series switch elements connected between the transmission input terminal and a first intermediate node, a second series switch circuit including second series switch elements connected between the first intermediate node and the first transmission and reception terminal, and a first shunt switch circuit including first shunt switch elements connected between the first intermediate node and a ground.

Abstract: A radio frequency switch apparatus includes a radio frequency switch, a dynamic bias circuit, and a switch control circuit. The radio frequency switch includes a first radio frequency switch circuit connected between a first signal terminal and an input terminal. The first radio frequency switch circuit includes a series switch and a shunt switch. The dynamic bias circuit is configured to generate a bias voltage and a buffer voltage lower than a battery voltage by a preset voltage, using the battery voltage and configured to output the bias voltage to a signal line connected to the input terminal. The switch control circuit is configured to generate first and second gate voltages to switch the first radio frequency switch circuit, based on a band selection signal, using the battery voltage and the buffer voltage.