Constant voltage power supply
First Claim
1. A power supply circuit for charging a battery having a temperature-voltage coefficient comprising a voltage supply, a reference means connected to said voltage supply for controlling the voltage of said supply, said reference means having a temperature coefficient similar to the said temperature coefficient of said battery being charged, output means connected to said voltage source, a current source connected to said reference means, said current source being independent of the voltage of said battery being charged, a zener diode comprising said reference, a transistor, said transistor having a base, an emitter, and a collector, said base of said transistor being connected to said zener diode, means for connecting said base emitter voltage to a battery to be charged, said transistor and said zener being so connected that said output voltage is equal to said base emitter voltage plus a constant times said zener voltage and said constant is equal to or less than one.
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Accused Products
Abstract
A constant voltage, current limited power supply primarily intended for use as a single cell, nickel cadmium battery charger. The nickel cadmium cell has a temperature characteristic of approximately minus 1.1 mV/*F. The system disclosed herein also has substantially this same temperature characteristic due to taking advantage of the intrinsic temperature characteristic of a forward-biased base-emitter junction of a silicon transistor. A forward-biased base-emitter junction is used as a system voltage reference and the voltage feedback arrangement permits the output voltage to be substantially above the reference voltage without reflecting a magnified voltage characteristic at the output.
8 Citations
1 Claim
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1. A power supply circuit for charging a battery having a temperature-voltage coefficient comprising a voltage supply, a reference means connected to said voltage supply for controlling the voltage of said supply, said reference means having a temperature coefficient similar to the said temperature coefficient of said battery being charged, output means connected to said voltage source, a current source connected to said reference means, said current source being independent of the voltage of said battery being charged, a zener diode comprising said reference, a transistor, said transistor having a base, an emitter, and a collector, said base of said transistor being connected to said zener diode, means for connecting said base emitter voltage to a battery to be charged, said transistor and said zener being so connected that said output voltage is equal to said base emitter voltage plus a constant times said zener voltage and said constant is equal to or less than one.
Specification
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- Resources
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Current AssigneeCooper Industries, Inc. (Eaton Corporation PLC.)
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Original AssigneeJoseph M. Allison
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InventorsAllison, Joseph M.
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Primary Examiner(s)Miller, J. D.
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Assistant Examiner(s)Hickey, Robert J.
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Application NumberUS05/312,709Time in Patent Office1,070 DaysField of Search320/39,40,31,32,35,36 322/28 323/68US Class Current320/150CPC Class CodesG05F 1/567 for temperature compensationH02J 7/007182 in response to battery voltageH02J 7/007194 of the battery
