A bias compensation circuit, coupled to an amplifying circuit, is disclosed. The bias compensation circuit comprises a transistor, comprising a first terminal, a second terminal and a control terminal; a first feedback transistor, comprising a control terminal, coupled to the first terminal of the transistor; a first terminal, coupled to the control terminal of the transistor; and a second terminal; and a second feedback transistor, comprising a control terminal, coupled to the first terminal of the transistor; a first terminal, coupled to the amplifying circuit; and a second terminal; and a first resistor, comprising a first terminal, coupled to the first terminal of the transistor; and a second terminal, configured to receive a first voltage.

A semiconductor chip includes a plurality of transistor rows. Corresponding to the plurality of transistor rows, a first bump connected to a collector of the transistor is arranged, and a second bump connected to an emitter is arranged. The transistor rows are arranged along sides of a convex polygon. A first land and a second land provided in a circuit board are connected to the first bump and the second bump, respectively. A first impedance conversion circuit connects the first land and the signal output terminal. A plurality of transistors in the transistor row are grouped into a plurality of groups, and the first impedance conversion circuit includes a reactance element arranged for each of the groups.

A semiconductor chip includes a plurality of transistor rows. Corresponding to the plurality of transistor rows, a first bump connected to a collector of the transistor is arranged, and a second bump connected to an emitter is arranged. The transistor rows are arranged along sides of a convex polygon. A first land and a second land provided in a circuit board are connected to the first bump and the second bump, respectively. A first impedance conversion circuit connects the first land and the signal output terminal. A plurality of transistors in the transistor row are grouped into a plurality of groups, and the first impedance conversion circuit includes a reactance element arranged for each of the groups.

A radio frequency module includes: a duplexer for a first communication band; a first power amplifier and a first low-noise amplifier connected to the duplexer; a second power amplifier and a second low-noise amplifier for a second communication band; and a switch that switches a connection of an antenna connection terminal between the second power amplifier and the second low-noise amplifier, wherein the first power amplifier and the second power amplifier are disposed on a first principal surface of a module substrate, the first low-noise amplifier and the second low-noise amplifier are incorporated in a semiconductor IC disposed on a second principal surface of the module substrate, and in a plan view of the module substrate, the distance between the first power amplifier and the semiconductor IC is greater than the distance between the second power amplifier and the semiconductor IC.

A radio frequency module includes: a duplexer for a first communication band; a first power amplifier and a first low-noise amplifier connected to the duplexer; a second power amplifier and a second low-noise amplifier for a second communication band; and a switch that switches a connection of an antenna connection terminal between the second power amplifier and the second low-noise amplifier, wherein the first power amplifier and the second power amplifier are disposed on a first principal surface of a module substrate, the first low-noise amplifier and the second low-noise amplifier are incorporated in a semiconductor IC disposed on a second principal surface of the module substrate, and in a plan view of the module substrate, the distance between the first power amplifier and the semiconductor IC is greater than the distance between the second power amplifier and the semiconductor IC.

A Doherty amplifier system is disclosed with a carrier amplifier configured to amplify a first portion of a radio frequency (RF) signal. A peaking amplifier with a peaking output is configured to amplify a second portion of the RF signal when it is above a power level threshold. A first inductor is coupled between the main output and a first middle node, and a second inductor is coupled between the first middle node and the peaking output. The first inductor and the second inductor are configured to have a first magnetic coupling to form a first impedance inverter. A third inductor is coupled between the peaking output and a second middle node, and a fourth inductor is coupled between the second middle node and an RF signal output. The third inductor and the fourth inductor are configured to have a second magnetic coupling to form a second impedance inverter.

A Doherty amplifier system is disclosed with a carrier amplifier configured to amplify a first portion of a radio frequency (RF) signal. A peaking amplifier with a peaking output is configured to amplify a second portion of the RF signal when it is above a power level threshold. A first inductor is coupled between the main output and a first middle node, and a second inductor is coupled between the first middle node and the peaking output. The first inductor and the second inductor are configured to have a first magnetic coupling to form a first impedance inverter. A third inductor is coupled between the peaking output and a second middle node, and a fourth inductor is coupled between the second middle node and an RF signal output. The third inductor and the fourth inductor are configured to have a second magnetic coupling to form a second impedance inverter.

A wireless access point is configured to regularly monitor the status of WLAN, WAN and ePDG data links to determine whether the current connections are sufficient to support VoWiFI services. When a device connects to the WLAN of the hub and attempts to switch from its VoLTE service to VoWiFi via the hub, the hub is configured to determine whether the current conditions can satisfy a VoWiFi connection. If the VoWiFi service can support the connection, the request is routed to the ePDG associated with the mobile device's subscriber LTE network. However, if the current conditions cannot satisfactorily support a VoWiFi connection such that incoming calls may be missed or the quality of active calls would not be clear, then the hub is configured to block the request so that the client device will time out and remain connected to VoLTE.

A wireless access point is configured to regularly monitor the status of WLAN, WAN and ePDG data links to determine whether the current connections are sufficient to support VoWiFI services. When a device connects to the WLAN of the hub and attempts to switch from its VoLTE service to VoWiFi via the hub, the hub is configured to determine whether the current conditions can satisfy a VoWiFi connection. If the VoWiFi service can support the connection, the request is routed to the ePDG associated with the mobile device's subscriber LTE network. However, if the current conditions cannot satisfactorily support a VoWiFi connection such that incoming calls may be missed or the quality of active calls would not be clear, then the hub is configured to block the request so that the client device will time out and remain connected to VoLTE.

Components of a power amplifier controller may support lower voltages than the power amplifier itself. As a result, a surge protection circuit that prevents a power amplifier from being damaged due to a power surge may not effectively protect the power amplifier controller. Embodiments disclosed herein present an overvoltage protection circuit that prevents a charge-pump from providing a voltage to a power amplifier controller during a detected surge event. By separately detecting and preventing a voltage from being provided to the power amplifier controller during a surge event, the power amplifier controller can be protected regardless of whether the surge event results in a voltage that may damage the power amplifier. Further, embodiments of the overvoltage protection circuit can prevent a surge voltage from being provided to a power amplifier operating in 2G mode.