摘要
建立了一种新型纯数字式加速度传感器的理论模型,通过检测吸合时间差检测加速度.该传感器不存在吸合电压的限制,避免了寄生电容的影响,其芯片面积远小于传统电容式加速度传感器;由于输出时间信号,可采用简单的纯数字接口电路检测.理论分析表明,质量块在两个检测电极之间的吸合时间差ΔT与加速度成正比关系,通过检测ΔT的变化即可检测加速度,其灵敏度、非线性与传统电容式加速度传感器相当.设计了一个悬臂梁-质量块结构的加速度传感器,芯片有效面积仅为0.03mm2,模拟结果显示,工作电压为8V,加速度为1gn时,吸合时间的变化ΔT为1.0554μs.采用TTL电路进行检测,其分辨率可以达到0.01gn,满量程±10gn工作时,非线性度为1.23%.
Principle of a novel digital accelerometer is presented here. The accelerometer consists of a beammass structure, with two driven electrodes on each side and two detected electrodes around the tip, and the mass is driven to be pulled-in to detected electrodes alternatively. The difference of the pull-in time from detected electrode 1 to 2 and 2 to 1 is proportional to the input acceleration. As the pull-in time signal can be detected by digital circuit, no analog circuit is needed. The system can be scaled down further since it has no limit of pull-in and parasitical capacitance effect. Accelerometer based on surface process is designed, which has a 0.03 mm^2 die area. Simulation results show that when driven voltage is 8 V and input acceleration is 1 gn, the difference of the pull-in time is 1. 055 4μs. As 10 ns resolution for TTL circuit is possible, a 0. 01 gn resolution can be obtained, while the full scale is ±10 gn and the nonlinearity is 1.23%.
出处
《传感技术学报》
CAS
CSCD
北大核心
2007年第9期1996-2000,共5页
Chinese Journal of Sensors and Actuators
基金
国家自然科学基金资助项目(60406009)
