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AssigneeMilwaukee Electric Tool Corporation
InventorKevin L. Glasgow
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A deep discharge protection circuit designed to be directly integrated into battery-operated devices having a battery, a power switch that controls the battery, and a load connected to the power switch. The protection circuit includes a thyristor or similar current-controlled, latched switch that has a control gate or input. The thyristor is coupled in series with the load. A capacitor or similar electric energy storage device is coupled to the load and to the control input of the thyristor. A resistor is coupled to the load and to the control input of the thyristor, in parallel to the capacitor. When the power switch is turned on, it delivers a current pulse to the capacitor. The capacitor briefly shorts and delivers a trigger current to the control input of the thyristor. The trigger current causes the thyristor to become conductive, which allows current to travel from the battery through the load to ground. The thyristor remains conductive so long as the current through the load remains at or above the holding current of the thyristor. If the current through the load drops below the holding current (as a result of the battery discharging), the thyristor turns off and remains off even if the battery experiences an open circuit recovery.
A discharge protection apparatus for a battery-powered device having a load, the apparatus comprising:
A discharge protection apparatus for a battery-powered device having a battery coupled in series to a power switch and a load coupled to the power switch, the apparatus comprising:
A discharge protection apparatus for a battery-powered device having a battery coupled in series to a power switch and a load coupled to the power switch, the apparatus comprising:
A method of preventing overdischarge of a battery connected to a power switch having an on position and an off position, the method comprising
Dependencies are inferred from the claim text.