CMOS热流量风速计恒温差控制环路的研究

Research on Constant Temperature Difference (CTD) Model Control Circuit of Thermal Flow Sensor

分析了恒温差控制模式在CMOS热流量风速计中遇到的振荡问题.为了能够用Pspice等电路软件对环路进行分析,建立了传感器热域到电域的转换模型.分析可知,检测芯片温度的PN结与加热电阻间的距离以及芯片材料的热容和热阻等参数对恒温差控制环路的工作频率有很大的影响.为了调节环路的振荡频率使它能更好的控制芯片温度并且优化测风速和风向时的性能,对上述芯片的参数都要仔细选取.实际电路测试验证了仿真结果.

The oscillation occurred in the constant temperature difference(CTD) control circuit of CMOS thermal flow sensors is analyzed.In order to simulate the entire controlling loop by the circuit software such as Pspice,a model which converts the thermal domain to electrical domain has been developed for the thermal sensor.From the analysis,we can see that the distance between the PN junction used to detect the temperature of the sensor and the resister used to heat the sensor,and other parameters such as the the...