一种带有外部噪声识别功能的AGC电路的设计

Design of an AGC circuit with external noise identification function

基于红外遥控接收芯片中自动增益控制电路的功能需求及其应用环境,设计了一种能够有效抑制外部环境光干扰、线性度高的自动增益控制电路。该电路在传统自动增益控制电路的设计理念基础上引入外部噪声识别功能,设计的核心子电路包括具有线性增益特性的可变增益放大器、比较器以及利用空闲时间识别外部噪声的信号检测与增益控制电路。电路基于0.25μm标准CMOS工艺设计,使用Hspice软件进行仿真验证。仿真结果表明:电源电压为3~5 V,温度为0~85℃时,可变增益放大器的可控增益范围至少可达-69.5~27.6 dB,且至少具有42 dB的线性增益控制范围。

Based on the functional requirements and application environment of the automatic gain control(AGC)circuit in the infrared remote control receiver,an AGC circuit with high linearity that can effectively suppress external ambient light interference was designed.An external noise identification function was introduced in the circuit.The core sub-circuits of this AGC circuit includes a variable gain amplifier(VGA)with linear gain characteristics,a comparator,and a signal detection and gain control circuit that uses blanking time to identify external noise.The circuit was designed with 0.25μm standard CMOS process and simulated&verified with Hspice software.The simulation results show that when the input voltage is 3-5 V and the temperature is 0-85℃,the controllable gain range of the VGA is at least-69.5-27.6 dB and the linear gain control range is at least 42 dB.