BATTERY CHARGER APPARATUS HAVING MULTIPLE MODES OF OPERATION AND AUTOMATIC SWITCHING THEREBETWEEN

• US 3,735,233 A
• Filed: 08/24/1970
• Issued: 05/22/1973
• Est. Priority Date: 08/24/1970
• Status: Expired due to Term

• Current Assignee: Richard Bertrem Ringle
• Original Assignee: Richard Bertrem Ringle
• Inventors: Ringle, Richard Bertrem
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/066,187
• Time in Patent Office: 1,002 Days
• Field of Search: 320/39,40,24,23,DIG.1,32
• US Class Current: 320/141
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 7/007182 in response to battery voltage

Abstract

A battery charging device is disclosed which charges a normal battery first in a constant current mode to a first intermediate terminal voltage, then in a modulated mode to a predetermined maximum terminal voltage, and then in a standby mode at a third predetermined float voltage. When the battery is attached to the charger in the standby mode and the terminal voltage falls below a predetermined level, the charger is automatically recycled to recharge the battery. If the charge cycle is interrupted by a momentary line voltage failure or other external malfunction, the charge cycle resumes when the malfunction is corrected. A small current is applied to any battery connected to the circuit regardless of its state of charge or the immediate past history of the charger or battery in previous cyclic operation; thus an abnormally discharged battery which may exhibit a very high input impedance and does not easily accept charge is charged by this device for gradual reinstatement and subsequent normal cyclic operation.

Claims

1. A circuit for automatically charging a battery to establish a terminal voltage at an optimum voltage level comprising:

source means for providing unilateral charging current;

charging current modulating means connected in series between said source means and the battery and including a transistor having an emitter-collector circuit connected in series between said source means and the battery and a base electrode adapted to serve as a control terminal;

means maintaining said modulating means in a maximum conductive condition for terminal voltages below a predetermined intermediate voltage level and including a bias current supplying resistance connected to said control terminal;

means responsive to said terminal voltage between said intermediate voltage level and a maximum voltage level to deactivate said maintaining means and to permit said modulating means to modulate the rate of charging current to the battery and including a voltage breakdown device having a breakdown voltage about equal to said intermediate terminal voltage; and

switch means responsive to the rate of charging current to substantially terminate said charging current through said modulating means to the battery when the charging current falls below a predetermined minimum and to thereafter prevent charging current through said modulating means to the battery for terminal voltages greater than a third predetermined voltage and including the parallel combination of a resistance and a first transistor adapted to function as a bistable switch, a second transistor adapted to control the state of said first transistor as a function of the terminal voltage on said battery and a biasing network connected to control said second transistor and in series with the battery so that said second transistor is responsive to the current through said battery, said parallel combination being connected in series with said voltage breakdown device and to said control terminal of said current modulating means and cooperating therewith so that as the terminal voltage of the battery increases, the supply of bias current to said modulating means transistor is reduced thereby modulating the rate of charging current flow to the battery as a function of the terminal voltage of the battery.

2. The circuit of claim 1 including means in series with said charging current modulating means and responsive to the state of said means to indicate that said modulating means is conducting current to the battery.

3. A circuit for automatically charging a battery to establish a terminal voltage at an optimum voltage level comprising:

source means for providing unilateral charging current;

charging current modulating means connected in series between said source means and the battery;

means maintaining said modulating means in a maximum conductive condition for terminal voltages below a predetermined intermediate voltage level;

means responsive to said terminal voltage between said intermediate voltage level and a maximum voltage level to deactivate said maintaining means and to permit said modulating means to modulate the rate of charging current to the battery and including a voltage breakdown device having a breakdown voltage about equal to said intermediate voltage level; and

switch means responsive to the rate of charging current to substantially terminate said charging current through said modulating means to the battery when the charging current falls below a predetermined minimum and to thereafter prevent charging current through said modulating means to the battery for terminal voltages greater than a third predetermined voltage and including the parallel combination of a resistance and a switch device, the parallel combination being connected in series with said voltage breakdown device and to a control terminal of said current modulating means and cooperating therewith to modulate the rate of charging current flow to the battery as a function of the terminal voltage of the battery.