Design Of Integrated Thermal Flow Sensors Using Thermal Sigma-delta Modulation

Large scale introduction of thermal flow sensors in consumer electronics, medical and automotive applications is seriously hampered by the limited response speed and the non-standardized format of the output signal of conventional thermal flow sensors. A thermal sigma-delta based feedback system can be used to provide an optimal interface for a wide variety of new as well as existing thermal flow sensors. Advantages of this system are an improved response time of the sensor system and an inherent analog to digital conversion of the measurement signal. Realized sensor implementations range from flow control in consumer electronics, respiration control, to industrial mass flow control.