Battery charging circuit
First Claim
1. A battery charger comprising a pair of battery terminals for connection to a rechargeable battery, a pair of input terminals for connection to an electrical power source, and an electrical charging circuit coupling said input terminals to said battery terminals for supplying a charging current to said battery terminals, said charging circuit comprising a switching transister having a control electrode and a current amplifier coupled to said input terminals permitting charging current flow to said battery terminals when a conventional 60 Hz. household outlet electrical source is applied to said input terminals only during those portions of a source cycle when the source voltage is below a predetermined voltage level substantially less than its maximum, and negative feedback means coupling the output of said current amplifier to said control electrode of said transistor whereby greater charging current flows at lower source voltage levels.
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Accused Products
Abstract
Disclosed is an improved circuit for recharging batteries. It can be used with alternating current power sources having a wide range of voltage and frequencies and also with low voltage direct current power sources. A transistor switch is connected in a feedback circuit to have, in effect, a variable resistance such that the charging current is high when the source potential is low and decreases to zero as the source potential increases. Charging efficiency is thereby significantly increased.
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Citations
12 Claims
- 1. A battery charger comprising a pair of battery terminals for connection to a rechargeable battery, a pair of input terminals for connection to an electrical power source, and an electrical charging circuit coupling said input terminals to said battery terminals for supplying a charging current to said battery terminals, said charging circuit comprising a switching transister having a control electrode and a current amplifier coupled to said input terminals permitting charging current flow to said battery terminals when a conventional 60 Hz. household outlet electrical source is applied to said input terminals only during those portions of a source cycle when the source voltage is below a predetermined voltage level substantially less than its maximum, and negative feedback means coupling the output of said current amplifier to said control electrode of said transistor whereby greater charging current flows at lower source voltage levels.
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12. A battery charger comprising a pair of battery terminals for connection to a rechargable battery, a pair of input terminals for connection to an electrical power source, and an electrical charging circuit coupling said input terminals to said battery terminals for supplying a charging current to said battery terminals, said charging circuit comprising a switch coupled to said input terminals permitting charging current flow to said battery terminals when a conventional 60 Hz. household outlet electrical source is applied to said input terminals only during those portions of a source cycle when the source voltage is below a predetermined voltage level substantially less than its maximum, said switch comprising a transistor and feedback means coupled to said transistor for varying the impedance of said switch in accordance with variations in source voltage whereby greater charging current flows at lower source voltage levels, said charging circuit including means for increasing said charging current with increasing source potential below said predetermined level.
Specification