用于无线通信系统的信号强度检测电路设计

为了解决传统的信号检测电路准确度不高,对温度和工艺变化抵抗能力不够的问题,建立了信号强度检测电路的系统模型.推导得到限幅放大器增益与信号强度检测单元误差的关系以及降低信号强度检测单元误差的方法.通过分析,得到在提高准确度的前提下减小限幅放大器增益随温度和工艺变化的方法.基于以上分析,引入增益加强结构,以提高限幅放大器增益的准确性和抵抗温度及工艺变化的能力.采用0.18 μm体硅(CMOS)工艺,1.8 V供电电源,面积为500 μm×200 μm的电路进行测试,结果表明:测试温度从-40 ℃变化到85 ℃时,该信号强度检测电路都可以提供55 dB的动态范围和大于55 MHz的带宽,其检测误差小于1.5 dB,电路功耗为1.89 mW,检测精度高达1.5 dB. 

Received Signal Strength Indicator Circuit for Wireless Communication Systems

To solve the problems that accuracy of traditional signal strength indicator circuit is low and resistance to temperature and process variations is not enough strong,a system model for RSSI(received signal strength indicator) circuit was set up.The relationship between limiting amplifier gain and signal strength detection unit error was derived,and measures to decrease the error were obtained.Through analyses ways to reduce gain change with temperature and process under the condition of improving accuracy were gained.Based on the analyses,a gain-enhanced structure was introduced to improve the accuracy of limiting amplifier gain and raise its ability to resist temperature and process variations.The designed circuit uses 0.18 μm bulk silicon(CMOS) technology with 1.8 V power supply,and its area is 500 μm × 200 μm.The test results show that the dynamic gain range of the circuit can reach 55 dB while test temperature changes from-40 °C to 85 °C.The circuit can provide a bandwidth greater than 55 MHz and its detection error is less than 1.5 dB.The power consumption of the circuit is 1.89 mW,and its detection accuracy is up to 1.5 dB.