一种用于频率合成器的自动频率校正电路

Design of Automatic Frequency Correction Circuit for Frequency Synthesizer

介绍了一种基于0.18μm标准CMOS工艺的自动频率校正电路,该电路采用开环粗调结构,使得频率合成器频率校正速度大大提高;采用编码预测性的二进制算法,使得频率校正的速度进一步提高。在电源电压3.3 V下进行仿真。结果显示,频率合成器的频率2150 MHz增加到2950 MHz,校正算法的控制码从0101变化到1111。可以看到自动频率校正算法的工作时间为48μs,随后锁相环开始工作,10μs后完成锁定过程。

Based on 0.18 μm CMOS process,an automatic frequency correction circuit was designed.The circuit adopts an open-loop coarse adjustment structure,which greatly increases the locking speed of the frequency synthesizer,and adopts a binary algorithm of coding predictability,so that the speed of frequency correction is further improved.Simulation was performed under a power supply voltage of 3.3 V,and the results showed that,frequency was change from 2 150 MHz to 2 950 MHz,capacitor array was change from 0101 to 1111.Frequency switching time is less than 58 μs,algorithm working time is 48 μs,PLL working time is 10 μs.