Amplifiers – With semiconductor amplifying device – Including plural amplifier channels
Reexamination Certificate
2007-06-05
2007-06-05
Pascal, Robert (Department: 2817)
Amplifiers
With semiconductor amplifying device
Including plural amplifier channels
Reexamination Certificate
active
11038060
ABSTRACT:
In order to supply a bias voltage to the base terminals of heterojunction bipolar transistors (HBTs) Q1to Q3connected in parallel to one another, resistors RB1to RB3and heterojunction bipolar transistors QB1to QB3whose base terminals are connected to the collector terminal thereof are provided. The amplifier transistors Q1to Q3have the same temperature characteristics as those of the bias-producing transistors QB1to QB3. With the bias circuit, it is possible to compensate for the temperature characteristics of the amplifier transistors Q1to Q3. Since the resistance values of the resistors RB1to RB3can be decreased, it is possible to suppress the decrease in the output power and to prevent the occurrence of the collapse phenomenon. Thus, it is possible to obtain a power amplifier capable of preventing the thermal runaway and compensating for the temperature characteristics without deteriorating the output characteristics.
REFERENCES:
patent: 5608353 (1997-03-01), Pratt
patent: 5629648 (1997-05-01), Pratt
patent: 6448859 (2002-09-01), Morizuka
patent: 6661290 (2003-12-01), Sugiura
patent: 2002/0097097 (2002-07-01), Sugiura
patent: A 2002-217378 (2002-08-01), None
Foregin Office Action dated Jan. 17, 2007 for Japanese Patent Application No. 2004-105051.
Nguyen Hieu
Pascal Robert
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