CAJ | 학술논문

设计了一种基于0.5 μm CMOS工艺的增益可控音频前置放大器电路.该电路采用直流音量控制方式控制前置放大器的增益,进而实现整体音频放大器的音量控制.外部输入的直流模拟电压经过片内模数转换器转换成数字控制信号,控制前置放大器的输入电阻与反馈电阻的比值,从而实现前置放大器的增益控制.该放大器能够实现32档的音量控制范围,增益从-50 dB变化到25 dB,电路版图面积为1.2 mm×0.8 mm.
설계료일충기우0.5 μm CMOS공예적증익가공음빈전치방대기전로.해전로채용직류음량공제방식공제전치방대기적증익,진이실현정체음빈방대기적음량공제.외부수입적직류모의전압경과편내모수전환기전환성수자공제신호,공제전치방대기적수입전조여반궤전조적비치,종이실현전치방대기적증익공제.해방대기능구실현32당적음량공제범위,증익종-50 dB변화도25 dB,전로판도면적위1.2 mm×0.8 mm.
A variable-gain pre-amplifier circuit for audio power amplifier was implemented in 0.5-μm CMOS process. In this circuit, DC volume control operation mode was adopted to control gain of the pre-amplifier, and by adjusting the gain of the pre-amplifier, volume of the whole audio power amplifier could be controlled. The input DC analog voltage signal was converted to digital control signals with an on-chip A/D converter, which was used to adjust ratio of feedback resistance to input resistance, thus realizing gain control of the pre-amplifier. The amplifier could offer a 32-step DC volume control from -50 dB to 25 dB. The circuit occupies a layout area of 1.2 mm×0.8 mm.