| 摘要 |
PROBLEM TO BE SOLVED: To provide a programmable variable gain amplifier having fixed change ratio of a gain without depending on a device parameter. SOLUTION: The programmable variable gain amplifier is equipped with: a variable gain amplifier 10 which outputs a first output signal according to a gain adjustment signal 21; a first simulation circuit 12 which has configuration equivalent to that of the variable gain amplifier 10 and outputs a first simulation signal based on the gain adjustment signal 21; a second simulation circuit 13 which has configuration equivalent to that of the variable gain amplifier 10 and outputs a second simulation signal based on a comparison gain adjustment signal 30; a difference detection circuit 17; a comparator 18 which outputs a binary comparison signal 33; a first count circuit 14; a second count circuit 15; and an addition circuit 16 which outputs the comparison gain adjustment signal 30. The comparison gain adjustment signal 30 is inputted to a register circuit 11 as a setting value of an address designated by a gain setting signal 32 when a setting value to be registered is updated. COPYRIGHT: (C)2011,JPO&INPIT |
