Battery charging circuit
First Claim
1. In a battery charging circuit having a solar energy source series-coupled to a secondary battery for applying a charging current thereto, the improvement comprising voltage detecting means coupled in parallel with said battery for detecting the state of charge of same, said detecting means including a constant voltage element and a detecting transistor including a control electrode referenced to said secondary battery potential for detecting the state thereof, and first and second current path electrodes coupled in series with said constant voltage element, and by-pass means including a first control electrode coupled to the detecting means and second and third current path electrodes connected in parallel with said battery for defining a by-pass current path for said charging current applied to said battery to prevent same from being overcharged, said by-pass means in response to the state of charge of said battery as detected at said first control electrode from said voltage detecting means, preventing the conduction of current in the current path defined by the second and third electrodes until said battery is charged to a predetermined voltage determined by the constant voltage element and thereafter permitting conduction of current in the current path defined by said by-pass means second and third electrodes, whereby the battery is by-passed when fully charged.
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Abstract
A battery charging circuit for effecting efficient charging of a battery by a solar energy source is provided. A voltage detecting circuit is coupled in parallel with a battery for detecting each state of charge of same, the detecting circuit including a constant voltage element. Transistor by-pass circuitry includes first and second current path electrodes connected in parallel with the battery. The transistor by-pass circuitry further includes a third control electrode coupled to the detecting circuit, and in response to the state of charging of the battery detected thereby, respectively effects one of an increase and decrease in the current carried by said current path electrodes.
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Citations
5 Claims
- 1. In a battery charging circuit having a solar energy source series-coupled to a secondary battery for applying a charging current thereto, the improvement comprising voltage detecting means coupled in parallel with said battery for detecting the state of charge of same, said detecting means including a constant voltage element and a detecting transistor including a control electrode referenced to said secondary battery potential for detecting the state thereof, and first and second current path electrodes coupled in series with said constant voltage element, and by-pass means including a first control electrode coupled to the detecting means and second and third current path electrodes connected in parallel with said battery for defining a by-pass current path for said charging current applied to said battery to prevent same from being overcharged, said by-pass means in response to the state of charge of said battery as detected at said first control electrode from said voltage detecting means, preventing the conduction of current in the current path defined by the second and third electrodes until said battery is charged to a predetermined voltage determined by the constant voltage element and thereafter permitting conduction of current in the current path defined by said by-pass means second and third electrodes, whereby the battery is by-passed when fully charged.
Specification