POWER AMPLIFYING DEVICE

摘要

A power amplifying device has a protection circuit (6) and a power amplifier (4) that amplifies power. The protection circuit (6) is provided with: a diode in which the output from the power amplifier (4) is inputted to the anode side; a capacitor, one side of which is connected to the cathode of the diode and the other side of which is connected to a ground or a power source (3); and a resistor, one side of which is connected to the cathode of the diode and the other side of which is connected to a ground or the power source (3). The time constant of the capacitor and the resistor is greater than the period of the signal outputted from the power amplifier (4). As a result, it is possible to obtain a power amplifying device that prevents damage to the power amplifier caused by high voltage that occurs when, in a transmission state, an antenna is changed from an unconnected to a connected state.