Power amplifying apparatus with dual-current control mode

A power amplifying apparatus comprising:

• a transistor mirror circuit adjusting currents respectively flowing through a main path and a mirror path connected in parallel to a power source terminal, according to variable resistance varying according to a gate voltage;
• a resistor mirror circuit connected to the transistor mirror circuit and adjusting the respective currents of the main path and the mirror path according to a fixed resistance ratio of the main path and the mirror path;
• a current controlling unit controlling a control current flowing through the main path with a pre-set constant current;
• a voltage adjusting unit providing a bias adjustment signal that corresponds to a difference voltage between a first voltage of a first node on the main path to which a current is output from the resistor mirror circuit and a second voltage of a second node on the mirror path to which a current is output from the resistor mirror circuit;
• and
• a bias circuit unit adjusting a bias of a power amplifying unit according to the bias adjustment signal from the voltage adjusting unit,
• wherein the transistor mirror circuit includes:
• a first MOS FET formed on the main path and having a source connected to the power source terminal, a gate connected to the gate voltage, and a drain;
• and
• a second MOS FET formed on the mirror path and having a source connected to the power source terminal, a gate connected to the gate voltage, and a drain, and the resistor mirror circuit includes:
• a first resistor having one end connected to the drain of the first MOS FET;
• and
• a second resistor having one end connected to the drain of the second MOS FET.