Active temperature compensation of thermal accelerometer for improved stability

Thermal accelerometers exhibit large changes in sensitivity with ambient temperature. Here we present an active compensation scheme that mitigates the effect of environmental temperature fluctuations on device performance. Ambient conditions are continuously monitored using the common mode resistance of a pair of symmetric thermistors. The heating power is adjusted using these readings to compensate for temperature fluctuations. This approach is based on signals that are already measured for detecting acceleration; thus it requires no additional power or design complexity. Implementing this approach with our high-stability ALD Platinum thermal accelerometer, we effectively eliminate the temperature dependence of the sensitivity. Across the measured range of 10
^o
C to 60
^o
C for a desired sensitivity of 0.08
^o
C/g, the standard deviation of the sensitivity fluctuations is less than 1%.