A compact sensor for measuring multiple gas flows has been designed and fabricated. The device consists in a single silicon chip where three independent flow sensing structures have been included. The sensing structures are differential micro-calorimeters, equipped with double heaters in order to perform drift-free offset compensation. The chip includes also a versatile electronic interface including a low noise chopper amplifier and an original closed loop heater driver capable of reducing the effects of pressure variations on the flow measurement. The chip has been designed using the BCD6s process of STMi-croelectronics. A post-processing step, based on anisotropic etching, is required to complete the smart sensor fabrication.
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