VARIABLE GAIN AMPLIFICATION CIRCUIT,申请号JP20090294893-传众专利搜索

VARIABLE GAIN AMPLIFICATION CIRCUIT

申请公布号：JP2011135478(A)

申请号：JP20090294893

申请日期：2009.12.25

申请公布日期：2011.07.07

申请人：

NEW JAPAN RADIO CO LTD

发明人：KOGANE TOMOHIRO

分类号：H03G3/12;H03F3/45;H03F3/68

主分类号：H03G3/12

摘要：PROBLEM TO BE SOLVED: To provide a variable gain amplification circuit in which an input/output range can be widened up to a power supply voltage. SOLUTION: This invention relates to the variable gain amplification circuit wherein a first operational amplifier 51 is disposed on an input stage, and a second operational amplifier 52 is disposed on an output stage, respectively. A first transconductance amplifier 53 is disposed on a feedback path of the first operational amplifier 51 and a second transconductance amplifier 54 is disposed between the first and second operational amplifiers 51 and 52, respectively. An input signal can be applied to the first operational amplifier 51 via a first resistor 61, and a current to flow to the first resistor 61 is made equal to a negative feedback current of the first operational amplifier 51. On the other hand, a second resistor 62 is provided between input and output terminals of the second operational amplifier 52, and the second operational amplifier 52 is employed of which the final stage is configured to fully swing. A current to flow to the second resistor 62 is made equal to an output current of the second transconductance amplifier 54, thereby widening an input/output range up to a power supply voltage. COPYRIGHT: (C)2011,JPO&INPIT