| 摘要 |
PURPOSE: To obtain a semiconductor power amplifier with low distortion and high efficiency by automatically adjusting the gate bias of a semiconductor amplifier element with a current corresponding to the level of high-frequency input power generated by a current circuit. CONSTITUTION: The current circuit 18 detects the level of the high-frequency input power between the gate electrode G of an FET 11 and the ground and generates the current corresponding to the level of the high-frequency input power. The current generated by the circuit 18 flows through the resistor R in a gate bias circuit 14 and the gate bias is automatically adjusted. Consequently, the drain bias current of the drain bias circuit 17 is controlled corresponding to the high-frequency input power to enable small-distortion, high-efficiency operation over the wide range of the high-frequency input power. The current circuit 18 has a Zener diode D1 connected to a resistor R1 in series and a capacitor C1 connected to the resistor R1 in parallel. |
