Apple Incorporated Two Accelerometers Into the iPhone 6 and 6 Plus to Minimize Power Consumption

[RaduTyrsina]

Apple has equipped the iPhone 6 and 6 Plus with two separate accelerometers, informs Chipworks' extensive iPhone 6 and 6 Plus teardown. According to the report, there's a three-axis Bosch BMA280 accelerometer and a MPU-6700 six-axis accelerometer from InvenSense.

Chipworks say that Apple may have decided to incorporate two accelerometers into the iPhone 6 and 6 Plus to both minimize power consumption and "improve the overall user experience." Here are some bits from the original report:

The InvenSense device can operate as a six axis inertial sensor, or as either a three-axis gyroscope or a three-axis accelerometer. It is rated to consume 3.4 mA in the six-axis mode, 3.2 mA in the gyroscope mode and 450 µA in the accelerometer normal mode. By contrast, the Bosch device operates as a 3-axis accelerometer only and it consumes 130 µA of current in the accelerometer normal mode. Both devices offer two low power levels of operation for the accelerometer function. The InvenSense device actually consumes less current in its lowest power mode, with a 1 Hz update rate.

The main benefit of the InvenSense is full six-axis integration of the data by the on-chip digital motion processor (DMP). This will provide a direct benefit for gaming and other applications that need sophisticated inertial sensing capabilities. In addition the InvenSense provides significantly higher sensitivity than the Bosch device. The price however, is higher power consumption.

The Bosch accelerometer is able to operate at a lower power than the InvenSense and it has a "much faster" cold start up time, at 3ms compared to 30ms. Chipworks suggests that it could be used for tasks where higher sensitivity is unneeded, such as rotating the screen from landscape to portrait mode or for pedometer functionality.

Source: Chipworks