Patent ID: 8368327
Filing Date: 2013-02-05
Classification: A61C

Abstract:
1. A system for maintaining performance of an electric toothbrush powered by a battery, comprising: a system for measuring the battery voltage of the electric toothbrush and the current value in a stator portion of the motor for the electric toothbrush from which current value the corresponding amplitude of movement of the workpiece of the toothbrush is then obtained; a circuit/program routine for changing the duty cycle or pulse width of the drive signal for the motor if the battery voltage drops below a first voltage threshold value and a circuit/program routine for changing the drive signal frequency if the amplitude falls below a first amplitude threshold value, to increase the amplitude of movement of the workpiece; and a circuit/program routine for terminating the operation of the appliance if the battery voltage drops below a second voltage threshold value which is lower than the first voltage threshold value and if the workpiece amplitude drops below a second amplitude threshold value which is lower than the first amplitude threshold value.