Bosch Sensortec Introduces Next-Gen Electronic Compass With Small Footprint And Very Low Power Consumption

With a size of just 2.2 x 2.2 mm2 and a power consumption as low as 190 µA it sets new standards for compactness and battery lifetime.

Design focus on package size and low power requirements

Our focus for the BMC150 design was reducing the footprint and thus to help our customers to save valuable PCB real estate, comments Bosch Sensortec CEO Stefan Finkbeiner. An equally important goal was increasing the measurement range. As the result, the BMC is the ideal eCompass module for innovative applications in battery-driven mobile devices such as smartphones, tablet computers and watches.

BMC150 combines a 3-axis geomagnetic sensor and a state-of-the-art 3-axis accelerometer in a single package. Its high integration translates into another benefit for users: It reduces the number of components that otherwise have to be handled and qualified separately. Both sensors form a logical and functional unit, since the g-vector generated by the accelerometer is required to calculate the tilt compensation for the azimuth data produced by the geomagnetic sensor. The accelerometer and the geomagnetic sensor in BMC150, however, can also be used as two fully functional independent devices.

Besides high integration, the sensor offers very high accuracy. Its exceptionally wide measurement range of +/- 1300 µT per axis makes it more tolerant to stray magnetic fields associated to loudspeakers or other magnetic components in smartphones. On the other hand, its extremely low noise of just 0.3 µT enables very accurate measurement.

Many applications for handheld devices such as user interface or navigation depend on an orientation vector. With eCompass library V3.0, Bosch Sensortec also offers a sensor data fusion software that performs the calculations for tilt compensation and thus generates precise heading information for compass applications. In cases where a highly dynamic orientation vector is indispensable – such as augmented reality or games – designers typically employ a gyro sensor to provide this information in a 9-axis sensor system. Along with Bosch Sensortec's FusionLib V3.0 algorithm, the 3-axis stand-alone gyro sensor BMG160 is the ideal complement to the BMC150.

Smart interrupt engine detects motion patterns

The inherent intelligence of the BMC150 helps to significantly reduce time to market for application developers. With its powerful and versatile interrupt system, the BMC150 greatly facilitates the design of a broad range of different applications. The integrated smart interrupt engine enables the sensor module to automatically identify motion patterns and situations. For instance, it detects free fall conditions, flat orientation on a table, tap sensing or even no motion at all for a definable period of time. These status data enable the implementation of many innovative features for mobile devices such as activating sleep mode and waking it up by tapping it with a finger.

Developers also benefit from the new FIFO buffer which acts as a temporary storage for measurement data until they are needed. This feature offloads the application processor further, effectively reducing the system's overall power consumption. The accelerometer section of the sensor can be adjusted to four different g ranges between +/- 2g and +/- 16g, enabling designers to select the g range that fits best their application.

The Bosch Sensortec BMC150 is available now.