一种用于X光成像的CMOS模拟△-∑调制器

A CMOS Analog △-Σ Modulator for X-ray Imaging System

设计了一个用于32通道X光成像系统前端的模拟△-∑调制器。基于一种通用的2阶1比 特结构,引入了对调制器环路状态进行复位的操作来避免在通道数据间发生相干性。Hspice和 Matlab下的仿真表明,在0.54μm标准CMOS工艺下,采用30 MHz的采样时钟,该调制器可以保 证对每个通道14位以上的转换精度。该调制器采用5 V电源,功耗小于40 mW,面积为1.13 mm× 0.92 mm,可作为专用硬核使用。

A A-2 modulator is designed for front-end data acquisition circuit of a 32-channel X-ray imaging system. A reset operation is used for the modulator loop state to eliminate the possible correlation between channels. With 30 MHz sampling clock, the Hspice and Matlab simulation result shows this 2nd-order 1-bit △-∑ modulator can achieve a conversion accuracy of 14 bits for each channel. This modulator hard core has less than 40 mW power consumption with a single 5 V supply voltage. The chip area is 1. 13 mm × 0. 92 mm.