| 摘要 |
<P>PROBLEM TO BE SOLVED: To stably accommodate manufacturing characteristic variations of elements and changes and variations in supply voltage. <P>SOLUTION: A low noise amplifier includes: an input terminal 2; a transistor 1 for amplifying an input signal input into the input terminal; an output terminal 3 for outputting an output signal of the transistor; a feedback amount adjustment circuit 10 for outputting an adjusted amplitude as a feedback amount of the output signal of the transistor; a bias circuit 9 for generating a bias current supplied to the transistor; a differential voltage comparator 11 for comparing the output voltage of the feedback amount adjustment circuit with a reference voltage and, if determining that the input signal causes gain suppression on the transistor, operating the bias circuit to increase the bias current to the transistor; a first input bias circuit 12 for generating the reference voltage and applying it to one input end of the differential voltage comparator; and a second input bias circuit 13 for adding a bias voltage to the output voltage of the feedback amount adjustment circuit and applying it to the other input end of the differential voltage comparator. <P>COPYRIGHT: (C)2012,JPO&INPIT |
