| US 7,522,001 B2 | ||
| Power amplifier | ||
| Kazuya Yamamoto, Tokyo (Japan); and Miyo Miyashita, Tokyo (Japan) | ||
| Assigned to Mitsubishi Electric Corporation, Tokyo (Japan) | ||
| Filed on Nov. 29, 2007, as Appl. No. 11/946,931. | ||
| Claims priority of application No. 2007-217269 (JP), filed on Aug. 23, 2007. | ||
| Prior Publication US 2009/0051437 A1, Feb. 26, 2009 | ||
| Int. Cl. H03G 3/10 (2006.01) | ||
| U.S. Cl. 330—285 [330/296; 330/288] | 8 Claims |
| 1. A power amplifier comprising:
a first amplifying device having input and output terminals and which amplifies a radio frequency signal;
a second amplifying device having an output terminal connected to the output terminal of the first amplifying device, and
an input terminal;
an emitter follower circuit which applies to the input terminal of the second amplifying device a voltage according to a reference
voltage applied to a reference terminal;
first and second resistors connected in series between the reference terminal and the input terminal of the first amplifying
device;
a first transistor having an emitter, a collector connected to the reference terminal, and a base to which a control voltage
is applied;
a third resistor connected between the emitter of the first transistor and a grounding point; and
a current mirror circuit which draws a current proportional to current input from the collector of the first transistor from
a connection point of the first resistor to the second resistor.
|