System and method for maintaining performance of battery-operated toothbrushes

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, at a selected time during the lifetime of operation of the battery, after each brushing event or a specified number of brushing events;
• a circuit/program routine for changing the pulse width of the drive signal for the motor for the electric toothbrush if the battery voltage drops below a first threshold value;
• and
• a circuit/program routine for terminating the operation of the toothbrush if the voltage drops below a second threshold value which is lower than the first threshold value.

A system for maintaining performance of an electric toothbrush, powered by a battery, comprising;

• a system for measuring the current in a stator portion of a motor supplying a drive signal for the electric toothbrush and for determining the amplitude of movement of a brushhead workpiece from the measured stator current;
• a circuit/program routine for changing the drive frequency of the appliance if the amplitude of movement of the workpiece falls below a first threshold value, to increase the amplitude of the workpiece to maintain performance of the appliance;
• and
• a circuit/program routine for terminating the operation of the appliance if the amplitude of movement of the workpiece drops below a second threshold value which is lower than the first threshold value.

A method for maintaining performance of an electric toothbrush powered by a battery, comprising the steps of:

• measuring the battery voltage of the electric toothbrush and the current a stator portion of the motor for the electric toothbrush from which the amplitude of movement of the toothbrush is obtained;
• changing the duty cycle or pulse width f the drive signal for the motor if the battery voltage drops below a first threshold value and changing the drive signal frequency of the appliance if the amplitude falls below a first amplitude threshold value to increase the amplitude of movement of the workpiece;
• and
• terminating the operation of the appliance if the battery voltage drops below a second voltage threshold value and if the workpiece amplitude drops below a second amplitude threshold.

A method for maintaining performance of an electric toothbrush powered by a battery, comprising the steps of:

• measuring the battery voltage of the electric toothbrush, at a selected time during the lifetime of operation of the battery. after each brushing event or a specified number of brushing events;
• changing the pulse width of the drive signal for the motor for the electric toothbrush if the battery voltage drops below a first threshold value;
• and
• terminating the operation of the toothbrush if the voltage drops below a second threshold value which is lower than the first threshold value.

A method for maintaining performance of an electric toothbrush powered by a battery, comprising the steps of:

• measuring the current in a stator portion of a motor supplying the drive signal for the electric toothbrush and for determining the amplitude of movement of the brushhead workpiece from the measured stator current;
• changing the drive signal frequency if the amplitude of movement of the workpiece falls below a first threshold value, so as to increase the amplitude of the workpiece to maintain performance of the appliance;
• and
• terminating the operation of the appliance if the amplitude of movement of the workpiece falls below a second threshold value Which is lower than the first threshold value.