DC to DC battery charger

• US 4,638,236 A
• Filed: 11/08/1984
• Issued: 01/20/1987
• Est. Priority Date: 11/08/1984
• Status: Expired due to Fees

• Current Assignee: A G Busch & Company Incorporated
• Original Assignee: A G Busch & Company Incorporated
• Inventors: Terrill, Larry R., Carr, Francis L.
• Primary Examiner(s): Hickey, R. J.
• Application Number:
  US06/669,663
• Time in Patent Office: 803 Days
• Field of Search: 320/2-5, 320/20, 320/21, 320/19, 363/26
• US Class Current: 320/104
• CPC Class Codes: H02J 7/1423 with multiple batteries
• CPC Class Codes: H02J 7/342 The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging with circuits for polarity protection H02J7/0034
• CPC Class Codes: Y10S 320/23 Capacitor
• CPC Class Codes: Y10S 320/24 Inductor
• CPC Class Codes: Y10S 320/28 Regulating transformer, e.g. high leakage, ferro-resonant

Abstract

A battery charger adapted for connection to a standard 12 volt vehicle battery through a cigarette lighter socket includes a transistorized saturable-transformer DC to AC inverter and an AC to DC rectifier for generating a potential higher than the potential from said 12 volt vehicle battery. An integrated circuit pulse width modulated current control is used to control charging current flow to a second battery to be charged and to maintain charging current at a safe level.

Claims

1. A DC to DC battery charger for a vehicle comprising:

adapter plug means for making electrical connections to a first battery through a cigarette lighter socket in said vehicle;

means for making electrical connections to a second battery to be charged;

a DC to AC converter and an AC to DC rectifier for elevating the voltage from said first battery to a voltage above that of said second battery;

integrated circuit means for generating a pulse width modulated current as a function of the charged condition of said second battery;

transistor switch means supplied with said pulse width modulated current for developing a charging voltage;

a choke coil and a capacitor serially connected to said transistor switch means; and

a diode connected across said choke coil and said capacitor whereby said capacitor is charged during pulses of current from said transistor switch means through said choke coil, said choke coil reversing polarity at the termination of said pulses of current and continuing to charge said battery through said diode, said DC rectified voltage being controlled by said integrated circuit means for regulating current through said choke coil.