基于肖特基势垒二极管整流的功率指示计设计

Design of a RSSI Based on Schottky Barrier Diode Rectifier

设计了一种适用于低中频接收机的功率指示计。采用肖特基势垒二极管作为整流器件,降低了电路设计的复杂度,减小了系统功耗;功率指示计中的限幅放大器采用交流耦合的方式,消除了输入直流失调的影响,降低了设计难度。电路基于0.18μm CMOS工艺进行设计,测试结果表明,设计的功率指示计针对-50~0dBm的10 MHz中频信号可以产生0.25~1.65V的直流电压,线性误差小于±1dB,在1.8V电源电压下,整体功耗仅为1.4mW。

A received signal strength indicator （RSSI） circuit for low-IF wireless receivers was designed. The Schottky-barrier-diode（SBD）-formed full wave rectifiers were used to extract signal envelope at the output of each gain stage in the limiting amplifier. Taking advantage of the 10 MHz intermediate frequency, the gain stages in the limiting amplifier were AC-coupled, and therefore the DC-offset accumulation was eliminated. The circuit was designed with 0.18μm CMOS process. Measurements results showed that the RSSI was able to generate 0.25 1.65 V voltage to indicate --50 - 0 dBm input strength, and the linearity error was less than ±1 dB. With 1.8 V power supply, the total power dissipation was only 1.4 mW.