Variable gain control circuit and integrated circuit device having the same

Abstract

A variable gain control circuit is provided comprising a bipolar transistor for amplifying an input signal applied to a base, and outputs an output signal via a collector; a serial exchanging unit connected between an emitter of the bipolar transistor; a first voltage node; a parallel exchanging unit connected between the collector of the bipolar transistor and the first voltage node, and wherein the gain of the variable gain control circuit increases in a high gain mode by activating the serial exchanging unit and deactivating the parallel exchanging unit, and the gain of the variable gain control circuit decreases in a low gain mode by deactivating the serial exchanging unit and activating the parallel exchanging unit.

Description

technical field [0001] The present invention relates to a variable gain control circuit, and more particularly to a variable gain control circuit embedded in an integrated circuit device. Background technique [0002] Variable gain control circuits are used to control the amount of transmission output gain depending on distance or other communication circumstances, particularly when transmitting signals and transmitting or receiving waves between a mobile communication terminal and a base station. Control of output gain improves power efficiency and prevents unnecessary current leakage into adjacent channels. [0003] figure 1 is the circuit diagram of a conventional variable gain control circuit. refer to figure 1 , the conventional variable gain control circuit includes an input matching circuit 111 , an analog control circuit 121 , an output matching unit 131 , bipolar transistors 141 - 143 and an inductor 151 . [0004] Similar to a differential amplifier, current fl...

AI Technical Summary

Problems solved by technology

Therefore, the integrated circuit device equipped with the variable gain control circuit 101 needs more space, has higher current consumption and parasitic effects

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