A low-cost built-in self-test method for thermally actuated resistive MEMS sensors
Résumé
This paper illustrates the experimental application of the LIMBO method, an identification method based on binary observations dedicated to the (self-) test of integrated electronic and electromechanical systems, such as MEMS. This method is an alternative for signal digitalization of the impulse response of a system, in using a single 1-bit ADC (i.e. a voltage comparator) instead of a N-bits ADC. The tested MEMS device is a micro-wire, used as a heating resistor, mounted inside a Wheatstone bridge. We show how the impulse response and the offset of the micro device are estimated only using binary inputs and outputs and straightforward calculations, which can easily be implemented on an FPGA. We also introduce for the first time a variant of LIMBO which strongly reduces the online computation needs as well as achieving best accuracy as the convergence gets reached. Unvaryingly, the LIMBO approach only requires a 1-bit ADC and a 1-bit DAC, and low computational needs which makes it very amenable to integration and highlights its suitability for the test of systems based on resistive sensor and/or actuator. Such a method being fully versatile, it can also be used for any other finite impulse response sensor and/or actuator, resistive or not.