SPICE Model with Lumped Circuits for A Thermal Flow Sensor

A novel lumped parameter SPICE model for a thermal flow sensor is presented. The model is constructed by 13 circuit cells consisting of thermal resistors and thermal capacitors. The circuit cell originates from the heat conduction equation using the Finite Differential Method, including the 2-D thermal conduction cell, the convection cell and the thermal capacity in the chip. Based on the thermal model of the flow sensor, the 2-D temperature distribution of the chip can be calculated with SPICE in both the constant power mode (CP) and constant temperature difference mode (CTD). As an example, the thermal anemometer in CTD mode is measured in the wind tunnel to verify the model. The simulation results show a reasonable agreement with the experiments, with an error less than 8%. The proposed model is valuable to design the thermal flow sensor with system-level simulation.