Battery charge indicating circuit
First Claim
Patent Images
1. A voltage indicator circuit for a DC power source, comprising:
- a switch connected to the DC power source for controlling the voltage applied to the remainder of said circuit;
a zener diode series connected between said switch and a plurality of series connected resistors;
a plurality of series connected resistors, one of which is connected to said zener diode;
a plurality of series connected light emitting diodes, each light emitting diode being connected in parallel with one of said resistors;
said zener diode scaling the voltage that is applied to said resistors and said light emitting diodes to a predetermined value.
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Abstract
A voltage indicator circuit for indicating a charge state of a power supply, such as a battery pack, is disclosed. The voltage indicator circuit includes a voltage divider circuit that connects to a plurality of series connected light sources, such as light emitting diodes. Upon activation of the voltage divider circuit, one or more of the light sources may illuminate to provide a visual indication of the current charge state of the power supply. More particularly, the number of light sources illuminated varies according to the charge state of the battery pack.
85 Citations
20 Claims
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1. A voltage indicator circuit for a DC power source, comprising:
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a switch connected to the DC power source for controlling the voltage applied to the remainder of said circuit;
a zener diode series connected between said switch and a plurality of series connected resistors;
a plurality of series connected resistors, one of which is connected to said zener diode;
a plurality of series connected light emitting diodes, each light emitting diode being connected in parallel with one of said resistors;
said zener diode scaling the voltage that is applied to said resistors and said light emitting diodes to a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A device for providing DC power, comprising:
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a battery pack; and
a battery charge indicator circuit connected to said battery pack to indicate a charge state of said battery pack;
a switch for controlling a flow of electric power from said battery pack to said battery charge indicator circuit, a zener diode connected in series, between said switch and said battery charge indicator circuit for scaling the voltage applied to said indicator circuit;
said battery charge indicator circuit further comprising;
a voltage divider circuit formed by a plurality of series connected resistors, the connections between adjacent resistors defining a plurality of respective nodes; and
a plurality of series connected light emitting diodes each having an anode connected to separate nodes of said voltage divider circuit. - View Dependent Claims (8, 9, 10)
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11. A battery powered device for supplying power, comprising:
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a battery having first and second terminals;
a voltage detection circuit, connected to said battery, for detecting a charge state of said battery and having at least two series connected light emitting diodes for generating a visual signal upon a flow of electric current from said battery to said voltage detection circuit;
a switch for controlling said flow of electric current between said battery and said voltage detection circuit; and
a zener diode connected in series between said voltage detection circuit and said switch. - View Dependent Claims (12, 13, 14, 15)
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16. A DC power source comprising:
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a battery pack; and
a battery charge indicator circuit connected to said battery pack to indicate a charge state of said battery pack, said battery charge indicator circuit further comprising;
zener diode connected in series directly between said battery pack and said voltage divider circuit, a zener diode limiting the voltage applied to said voltage divider circuit to a predetermined value;
said voltage divider circuit having a first, second, third, and fourth resistor connected in series;
a first light emitting diode connected in parallel to said second resistor;
a second light emitting diode connected in parallel to said third resistor;
a third light emitting diode connected in parallel to said third resistor; and
a switch for controlling a flow of electric power from said battery pack to said battery charge indicator circuit. - View Dependent Claims (17, 18, 19, 20)
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Specification