Universal battery charger
First Claim
Patent Images
1. A battery charger, comprising:
- a source of electrical power for providing signals of cyclically varying amplitude;
a switching device that is triggerable for coupling at least a portion of the varying amplitude signals to a battery to be charged;
a trigger circuit for providing a trigger signal to the switching device;
a logical ANDing circuit having at least two inputs for receiving electrical signals corresponding to criteria that must be satisfied before the switching device can be triggered, said logical ANDing circuit having an output for enabling the trigger circuit so that when the trigger criteria is satisfied, the switching device is triggered; and
a trigger level detector coupled to one input of said logical ANDing circuit and responsive to a predetermined amplitude of the varying amplitude signal for enabling said ANDing circuit when the varying amplitude signal is below a predefined trigger level.
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Abstract
A battery charger having an input receptacle, and different AC electrical cords pluggable therein for adapting the charger to a variety of different AC distribution systems. Portions of rectified signals are coupled by a triggerable switching device to a battery to be charged. The switching device is triggered only on a negative slope portion of the rectified signal, at a specified rectified signal amplitude, only when a battery is connected to the charger, and when the battery indeed requires charging.
48 Citations
23 Claims
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1. A battery charger, comprising:
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a source of electrical power for providing signals of cyclically varying amplitude; a switching device that is triggerable for coupling at least a portion of the varying amplitude signals to a battery to be charged; a trigger circuit for providing a trigger signal to the switching device; a logical ANDing circuit having at least two inputs for receiving electrical signals corresponding to criteria that must be satisfied before the switching device can be triggered, said logical ANDing circuit having an output for enabling the trigger circuit so that when the trigger criteria is satisfied, the switching device is triggered; and a trigger level detector coupled to one input of said logical ANDing circuit and responsive to a predetermined amplitude of the varying amplitude signal for enabling said ANDing circuit when the varying amplitude signal is below a predefined trigger level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A battery charger, comprising:
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means for rectifying an AC signal; a switching device that is triggerable for coupling at least a portion of the rectified AC signal to a battery to be charged; a slope detector for providing a first enable signal during at least a portion of a negative slope of the rectified AC signal; a trigger circuit responsive to a predefined trigger level occurring on said rectified waveform for providing a second enable signal; and a combining circuit for combining the first and second enable signals for triggering said switching device at said trigger level and on a negative slope of the AC signal, and said switching device remains conductive so long as the trigger level on the AC signal exceeds a voltage of about that of the battery terminal voltage. - View Dependent Claims (11, 12, 13, 14)
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15. A method for charging a battery, comprising the steps of:
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rectifying AC signals and coupling the rectified signals to a switching device; coupling at least a portion of the rectified AC signals to the battery if the switching device is triggered on; triggering the switching device on a negative slope portion of the AC signals and at a predefined amplitude of the negative slope for providing substantially constant amplitude pulses to a battery to be charged, said pulses having an amplitude independent of the peak voltage and independent of frequency variations of the rectified AC signals; and comparing the terminal voltage of the battery with a reference to determine whether the battery requires charging, and allowing the switching device to be triggered so long as the battery requires charging. - View Dependent Claims (16, 17, 18)
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19. A battery charger, comprising:
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a rectifier for converting AC signals into rectified signals; a switching device that is triggerable to couple at least portions of the rectified signals to a battery to be charged; a logical ANDing circuit having plural inputs, and an output for enabling the switching device to be triggered; a trigger level detector for sensing the rectified signal and providing an output when the instantaneous voltage of the rectified signal is below a specified level, said trigger level detector output being coupled to an input of said logical ANDing circuit; a negative slope detector producing an output during a time period of a negative slope portion of the rectified signal, said negative slope detector output being coupled to an input of said logical ANDing circuit; a full charge detector circuit responsive to the battery terminal voltage for providing an output to an input of said logical ANDing circuit when said battery terminal voltage is below a specified voltage; and a battery detector circuit responsive to the connection of a battery to the battery charger, for providing an output to an input of said logical ANDing circuit; and whereby said logical ANDing circuit is responsive to the inputs thereof for enabling said switching device to be triggered. - View Dependent Claims (20, 21, 22, 23)
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Specification