Omnipolar Hall Sensor GX471 Acts as a Position Detector in Electric Toothbrushes

An electric toothbrush produces high frequency vibration of a brush head by rapid rotation or vibration of an electric motor. The electric toothbrush includes: a handle portion containing a power drive system; a brush head assembly including a brush head arm and a brush element at a distal end thereof; a drive train assembly responsive to a drive signal of the power drive assembly for generating movement of the brush head assembly; a magnet positioned such that it moves in accordance with the movement of the brush head assembly which generates a magnetic field; a Hall effect sensor mounted within the magnetic field wherein the response of the magnetic field has a phase shift with respect to the phase of the drive signal and a processor which has a phase shift relative to the phase of the drive signal and an all-pole Hall effect sensor GX471 which has a phase shift relative to the phase of the signal has a phase shift and a processor for determining the phase shift of the Hall sensor output caused by a load on the brush element during a brushing operation and for generating a signal indicative of said load based on stored information within the appliance that correlates the value of the phase shift with the load.

We recommend the GX471, an all-pole Hall, which is an all-pole Hall effect sensor device using mixed-signal CMOS technology. It incorporates advanced chopper stabilization technology, which allows the device to provide an accurate and stable magnetic switching operating point. The operating voltage can be as low as 2.5V, making it well suited for battery-powered applications with micro-power technology, and the optimized sleep mode greatly extends its lifetime.

The GX471 is a low-power, high-sensitivity bipolar Hall switch chip designed and manufactured using a CMOS process. The chip device internally integrates a voltage regulator, Hall voltage generator, small signal amplifier, chopper regulator, Schmitt trigger and CMOS output driver. The chip is characterized by good temperature stability, strong stress resistance, high sensitivity, and operating voltage of 2.1V ~ 5.5V. TO92S inline package, SMD SOT23-3L package, and the package are in line with RoHS environmental standards.