Invention Grant
- Patent Title: Variable gain amplifier compensating frequency response thereof
- Patent Title (中): 可变增益放大器补偿其频率响应
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Application No.: US13401887Application Date: 2012-02-22
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Publication No.: US08729452B2Publication Date: 2014-05-20
- Inventor: Taizo Tatsumi
- Applicant: Taizo Tatsumi
- Applicant Address: JP Osaka
- Assignee: Sumitomo Electric Industries, Ltd.
- Current Assignee: Sumitomo Electric Industries, Ltd.
- Current Assignee Address: JP Osaka
- Agency: Smith, Gambrell & Russell, LLP
- Priority: JP2011-040098 20110225
- Main IPC: H03F3/08
- IPC: H03F3/08 ; H03G3/20

Abstract:
A variable gain amplifier canceling the dependence of the frequency bandwidth thereof on the gain is disclosed. The variable gain amplifier includes a differential stage with a cascade transistor put between an amplifying transistor and a load resistor. The amplifier further includes a current supplier and a current extractor. The current supplier extracts a current flowing in the second transistor by supplying an additional current to the amplifying transistor. The current extractor adds the additional current flowing in the load resistor which is extracted by the additional current by the current supplier. The bias condition of the load resistor is kept substantially constant independent of the equivalent impedance of the cascade transistor.
Public/Granted literature
- US20120217381A1 VARIABLE GAIN AMPLIFIER COMPENSATING FREQUENCY RESPONSE THEREOF Public/Granted day:2012-08-30
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