Battery charging circuit
First Claim
1. A circuit for charging a battery of an appliance from a power source having a power source voltage, comprising:
- an electromagnetic transformer having a primary coil with first and second terminals and a secondary coil;
rectifying means electrically connected between said secondary coil and said battery;
an electrical series circuit including a first electronic switch having a first control lead, a first resistor and said primary coil, said series circuit being electrically connected in parallel with said power source;
first capacitor means electrically connected between said secondary coil and said first control lead for substantially reducing reverse voltage pulses transmitted to said first control lead;
a second electronic switch having a second control lead, said second electronic switch being electrically connected to said first control lead;
control signal supply means for simultaneously supplying said second control lead with a first electrical control signal proportional to the current flowing through said primary coil and a second electrical control signal proportional to said power source voltage;
a first diode having a first anode and a first cathode, said first diode being electrically connected in parallel with said primary coil with said first cathode being electrically connected to said first terminal of said primary coil; and
a Zener diode electrically connected in series with said first diode and in parallel with said primary coil, and having a second anode and a second cathode, said second anode being electrically connected to said first anode and said second cathode being electrically connected to said second terminal of said primary coil.
1 Assignment
0 Petitions
Accused Products
Abstract
A battery charging circuit having an electromagnetic transformer with primary and secondary coils, a rectifier connected between the secondary coil and the battery, a first transistor connected in series with the primary coil and a resistor to form a circuit in parallel with a power source, the base of the first transistor being connected to the secondary coil, and a second transistor electrically connected to the base of the first transistor. The first transistor has a high switching frequency, and the battery is charged with a constant reverse current during its blocking phase, regardless of the power source voltage. The first transistor is protected from reverse kick-back voltage pulses induced during its blocking phase by the provision of a diode and Zener diode connected in series across the primary coil and a capacitor interposed between the secondary coil and the base of the first transistor.
155 Citations
4 Claims
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1. A circuit for charging a battery of an appliance from a power source having a power source voltage, comprising:
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an electromagnetic transformer having a primary coil with first and second terminals and a secondary coil; rectifying means electrically connected between said secondary coil and said battery; an electrical series circuit including a first electronic switch having a first control lead, a first resistor and said primary coil, said series circuit being electrically connected in parallel with said power source; first capacitor means electrically connected between said secondary coil and said first control lead for substantially reducing reverse voltage pulses transmitted to said first control lead; a second electronic switch having a second control lead, said second electronic switch being electrically connected to said first control lead; control signal supply means for simultaneously supplying said second control lead with a first electrical control signal proportional to the current flowing through said primary coil and a second electrical control signal proportional to said power source voltage; a first diode having a first anode and a first cathode, said first diode being electrically connected in parallel with said primary coil with said first cathode being electrically connected to said first terminal of said primary coil; and a Zener diode electrically connected in series with said first diode and in parallel with said primary coil, and having a second anode and a second cathode, said second anode being electrically connected to said first anode and said second cathode being electrically connected to said second terminal of said primary coil. - View Dependent Claims (2, 3, 4)
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Specification