High-frequency power amplifier and communication device
It is an object of the present invention to provide a high-frequency power amplifier capable of improving the linearity at the time of high output by preventing decrease in power of bias supply transistor. The high-frequency power amplifier is a high-frequency power amplifier including high-frequency power amplifier transistors and connected in multiple stages and bias supply transistors and each of which supplies bias current to a base of a corresponding one of said high-frequency power amplifier transistors, and each of which is connected to a common power supply terminal which is further connected to a collector of the high-frequency power amplifier transistor at a first stage among said high-frequency power amplifier transistors, and a passive element connected between the common supply terminal and a collector of the corresponding one of said bias supply transistors connected to the high-frequency power amplifier transistor at the first stage.
1. A high-frequency power amplifier, comprising:
high-frequency power amplifier transistors connected in multiple stages; and
bias supply transistors, each of which supplies a bias current to a base of a corresponding one of said high-frequency power amplifier transistors, and each of which is connected to a common power supply terminal which is further connected to a collector of the high-frequency power amplifier transistor at a first stage among said high-frequency power amplifier transistors, and
a passive element connected between the common supply terminal and a collector of the corresponding one of said bias supply transistors connected to the high-frequency power amplifier transistor at the first stage.
2. The high-frequency power amplifier according to claim 1 , further comprising
a diode connected between a base of a corresponding one of said bias supply transistors and a ground.
3. The high-frequency power amplifier according to claim 1 , further comprising:
a first temperature compensation transistor having:
a collector connected to a collector of a corresponding one of said bias supply transistors;
an emitter grounded via a first resistor; and
a base connected to a base of the corresponding one of said bias supply transistors; and
a second temperature compensation transistor having:
a collector connected to the base of the corresponding one of said bias supply transistors;
a base connected to the emitter of said first temperature compensation transistor; and
an emitter which is grounded.
4. The high-frequency power amplifier according to claim 1 ,
wherein the common power supply terminal is connected to collectors of transistors in the multiple stages, and
said high-frequency power amplifier further comprises
a passive element connected between the common power supply terminal and a collector of one of said bias supply transistors among the transistors in the multiple stages.
5. The high-frequency power amplifier according to claim 1 ,
wherein said passive element is a resistor.
6. The high-frequency power amplifier according to claim 5 ,
wherein a resistance value of the resistor ranges from several hundred ohms to several thousand ohms.
7. The high-frequency power amplifier according to claim 1 ,
wherein said passive element is an inductor.
8. The high-frequency power amplifier according to claim 7 ,
wherein an inductance value of the inductor is several nanohenries.
9. The high-frequency power amplifier according to claim 1 ,
wherein said passive element is a serial connection of a resistor and an inductor.
10. The high-frequency power amplifier according to claim 9 ,
wherein the resistance value of the resistor ranges from several hundred ohms to several thousand ohms, and the inductance value of the inductor is several nanohenries.
11. A communication device, comprising:
a high-frequency power amplifier having:
high-frequency power amplifier transistors connected in multiple stages; and
bias supply transistors, each of which supplies a bias current to a base of a corresponding one of said high-frequency power amplifier transistors, and each of which is connected to a common power supply terminal which is further connected to a collector of the high-frequency power amplifier transistor at a first stage among said high-frequency power amplifier transistors, and
a passive element connected between the common supply terminal and a collector of the corresponding one of said bias supply transistors connected to the high-frequency power amplifier transistor at the first stage.