Patent ID: 8148947
Filing Date: 2012-04-03
Classification: B26B,G01R

Abstract:
1. A discharge state indicator circuit comprising: a battery, a motor connected to the battery to operate one of an electric toothbrush an electric shaver, the motor comprising an inductive load, a controllable switch connected in series with the inductive load and the battery, a display element connected in series with the inductive load and the battery, and a control circuit comprising a control output coupled to the controllable switch, the control circuit to compare a voltage of the battery with a first voltage threshold and a second voltage threshold and to operate the controllable switch via the control output based on the comparisons, wherein when the motor is powered by the battery and when the voltage of the battery is less than the first voltage threshold, the control output of the control circuit causes the controllable switch to open such that the motor is no longer powered by the battery and such that inductive energy stored in the inductive load is recovered and supplied to the display element and to the battery, wherein the inductive energy causes the display element to generate a display output and causes the battery to recover to a voltage greater than the first voltage threshold, wherein when the battery recovers to a voltage greater than the second voltage threshold, the output of the control circuit causes the controllable switch to close such that the motor is powered the battery, and wherein successive cycles of inductive energy recovery cause the display element to provide a flashing indication.