Battery charger

• US 4,105,962 A
• Filed: 11/08/1976
• Issued: 08/08/1978
• Est. Priority Date: 03/21/1975
• Status: Expired due to Term

• Current Assignee: Landis Tool Company
• Original Assignee: Landis Tool Company
• Inventors: Scott, Donald K. Jr., McIntosh, Michael D.
• Primary Examiner(s): Hickey, Robert J.
• Application Number:
  US05/739,681
• Time in Patent Office: 638 Days
• Field of Search: 320/32, 320/35, 320/36, 320/22-24, 320/39
• US Class Current: 320/153
• CPC Class Codes: H02J 7/007192 in response to temperature

Abstract

A constant voltage battery charger comprising a voltage regulator adapted to be supplied with D.C. voltage having a predetermined, constant level, means for establishing a regulator output voltage predetermined to define, at a selected temperature, a charging voltage equal to the charging voltage of a battery at that temperature including an operational amplifier means for supplying a predetermined voltage to the non-inverting input of the operational amplifier, and variable means for supplying voltage as a function of regulator output voltage to the inverting input of the operational amplifier, the variable means being selectively variable over a given range so that the predetermined output voltage can be defined at the selected temperature.

Claims

1. A constant voltage battery charger comprising

a three terminal voltage regulator having input, output and reference terminals adapted to be supplied with D.C. voltage having a predetermined, constant level,

means for continuously varying the reference voltage with the amount of charge required to establish a constant charging voltage whereby the rate of charge of a battery will be continuously variable with the state of charge of the battery,

said continuously varying means including,

an operational amplifier,

means for supplying a predetermined voltage to the noninverting input of said operational amplifier comprising a second operational amplifier and means for selectively varying the gain of said second operational amplifier as a function of temperature,

means for supplying voltage as a function of regulator output voltage to the inverting of said operational amplifier, said inverting input voltage supplying means including means for selectively varying said inverting input voltage over a given range so that a predetermined output voltage can be defined at a selected ambient temperature, and means for supplying the output voltage of said operational amplifier to said reference terminal.

2. A constant voltage battery charger comprising

a three terminal voltage regulator having input, output and reference terminals adapted to be supplied with D.C. voltage having a predetermined, constant level,

means for continuously varying the reference voltage with the amount of charge required to establish a constant charging voltage whereby the rate of charge of a battery will be continuously variable with the state of charge of the battery,

said continuously varying means including,

an operational amplifier,

means for supplying a predetermined voltage to the noninverting input of said operational amplifier,

means for supplying voltage as a function of regulator output voltage to the inverting input of said operational amplifier,

said inverting input voltage supplying means including means for selectively varying said inverting input voltage over a given range so that a predetermined output voltage can be defined at a selected ambient temperature,

said inverting input voltage varying means comprising switch means, and

means for opening said switch means when said three terminal regulator is not supplied with the D.C. voltage having said predetermined, constant level,

and means for supplying the output voltage of said operational amplifier to said reference terminal.

3. A constant voltage battery charger according to claim 2, wherein said switch means comprises a transistor selectively biased by said predetermined D.C. voltage.

4. A constant voltage battery charger comprising

a three terminal voltage regulator having input, output and reference terminals adapted to be supplied with D.C. voltage having a predetermined, constant level,

means for continuously varying the reference voltage with the amount of charge required to establish a constant charging voltage whereby the rate of charge of a battery will be continuously variable with the state of charge of the battery,

means for preventing the reference voltage of said three terminal voltage regulator from exceeding a predetermined level, said preventing means comprising,

a second operational amplifier,

means for supplying a predetermined voltage to the non-inverting input of said second operational amplifier,

means for supplying a voltage to the inverting input of said second operational amplifier equal to the voltage supplied to the non-inverting input thereof when the reference voltage equals said predetermined level, and

means for increasing the voltage supplied to the inverting input of said second operational amplifier as said reference voltage increases above said predetermined level,

said continuously varying means including,

an operational amplifier,

means for supplying a predetermined voltage to the noninverting input of said operational amplifier,

means for supplying voltage as a function of regulator output voltage to the inverting input of said operational amplifier, said inverting input voltage supplying means including means for selectively varying and inverting input voltage over a given range so that a predetermined output voltage can be defined at a selected ambient temperature, and means for supplying the output voltage of said operational amplifier to said reference terminal.