Safety circuit for charging devices
AssigneeHewlett-Packard Development Company, L.P.
InventorsLonnie W. Adelman, Clarence R. King, III, Patrick Regan, Jose De Jesus Ramirez
Life of this patent
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Abstract
Systems and methods for implementing a safety circuit in charging devices are disclosed. In an exemplary embodiment, a method may include closing a latch to stop delivery of a charging current to a battery when voltage produced by the battery indicates that the battery is non-rechargeable. The method may also include dropping a threshold from an initial value for the voltage produced by the battery to a baseline value so that the latch remains closed even if the voltage produced by the non-rechargeable battery drops below the initial value of the threshold. The method may also include resetting the latch each time a battery is connected to the charging device.
Claims16
A method comprising:
- a closing a latch to stop delivery of a charging current to a battery when voltage produced by the battery indicates that the battery is non-rechargeable;
- dropping a threshold from an initial value for the voltage produced by the battery to a baseline value so that the latch remains closed even if the voltage produced by the non-rechargeable battery drops below the initial value of the threshold;
- resetting the latch each time a battery is connected to the charging device;
- and
- providing a non-charging current to a device including the battery to keep the device powered on even after charge cutoff, the non-charging current is less than a level of current that vents a non-rechargeable battery.
A safety circuit for a charging device comprising:
- a first comparator configured to compare voltage produced by a battery to a threshold, output from the first comparator indicating if a battery is a rechargeable battery or a non-rechargeable battery;
- a second comparator receiving the output from the first comparator, the second comparator latching closed to stop delivery of a charging current to the battery if the battery is non-rechargeable;
- an FET connected to the first comparator, if the battery is a non-rechargeable battery, the FET turning on to drop the threshold from an initial value to a baseline value to latch the first comparator in a high state, and the second comparator in a low state, even if voltage produced by the battery drops below the initial value;
- and
- a reset circuit coupled to the first comparator and the second comparator, the reset circuit issuing a reset signal to the first comparator and the second comparator each time a battery is connected to the charging device.
Dependencies are inferred from the claim text.