Efficient integration through CMOSens® Technology
The combination of conventional CMOS semiconductor technology and sensors in small spaces has been known as CMOSens® Technology for more than 10 years and is a recognized standard. CMOSens® Technology enables the fusion of the sensor element with analogue and digital processing electronics on a tiny CMOS silicon chip. The resulting sensor chip records the required physical parameters precisely and reliably. Sensirion is regarded as the world leader in this field. Sensirion develops CMOSens humidity and temperature sensors and mass flow sensors for a range of applications in the medical, automotive and consumer products industries, and supplies millions of units to customers worldwide. Sensirion's humidity and temperature sensors are widely established in the automotive industry.
Humidity and temperature sensors based on CMOSens® technology contain a humidity-sensitive substrate and a conventional semiconductor temperature sensor. Both elements are combined on a semiconductor chip with analogue and digital processing electronics. The electronics contain individual calibration data for each sensor, thus ensuring the highest measuring precision for the entire lifetime of the sensor module. A digital (I2C) interface enables the efficient, robust connection of the sensor to a common microcontroller and can be integrated easily in a multisensor bus system controlled by a microcontroller. The microcontroller, in turn, conducts the communication of all recorded data via a LIN or CAN transceiver. Sensors based on this technique allow simple and efficient integration of additional modules on a multisensor platform.
As an SMD component, the CMOSens humidity and temperature sensor allows standard reflow soldering on to a printed circuit board, thus enabling efficient combination of the sensor module with other components to create a multisensor platform.
Four-in-one: the combined rain, light, solar and condensation sensor
The base of the rear-view mirror on the windscreen is becoming increasingly important to the intelligence of the vehicle. It is essential to avoid impairing the driver's field of vision, yet this spot is ideal for the integration of more safety and comfort systems. To use the space most efficiently, it makes sense to integrate a number of different sensors into a single system. CMOSens® Technology has made it possible to create the world's first combined rain, light, solar and condensation sensor. A combined sensor of this type is mounted on the inside of the windscreen and connected to the LIN bus. The humidity sensor performs the condensation function by determining the humidity directly at the windscreen and transmitting the information to the air conditioning control. In damp and cold weather, the air conditioning system can take measures to prevent the windscreen misting up, ensuring optimal vision for the driver. The other sensors in such a multisensor platform recognise not only the intensity of rain to control the windscreen wiper system and the ambient light to control the headlights and rear lights, but also the intensity of sunlight and humidity as salient information for the air conditioning system.
More functionality in the same space: the integrated mass air flow sensor
The continuing reduction of emissions and fuel consumption requires more complex electronic systems for control and diagnostics. The task is to add additional functions to existing systems without requiring more space. One example is the mass air flow sensor, which determines the mass air flow and temperature of the air taken in by the engine. For the next generation of petrol and diesel engines, humidity will be determined in addition to these two factors, making it possible to optimise exhaust gas recirculation and minimize nitrogen oxide emissions in diesel engines. This additional indicator had to be integrated into the existing mass air flow sensor. The small size of the humidity sensor and its simple electronic integration into the existing electronics made possible the world's first integrated mass air flow sensor with humidity measurement.
Microsensors based on CMOSens® Technology are driving innovation in vehicle manufacturing. Effective solutions for electronic systems can be developed that increase the safety and efficiency of vehicles, taking into account the very tight installation spaces.