BATTERY CHARGING CIRCUIT UTILIZING MULTIVIBRATOR LOCKING MEANS

• US 3,576,487 A
• Filed: 12/22/1969
• Issued: 04/27/1971
• Est. Priority Date: 12/22/1969
• Status: Expired due to Term

• Current Assignee: Robert F. Chase
• Original Assignee: Robert F. Chase
• Inventors: Chase, Robert F.
• Application Number:
  US04/887,030
• Time in Patent Office: 491 Days
• US Class Current: 320/139
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: Y10S 320/12 Precharging analysis, e.g. determining presence of battery
• CPC Class Codes: Y10S 320/19 Charger status, e.g. voltmeter
• CPC Class Codes: Y10S 320/22 Line impedance, e.g. resistor

Abstract

A battery charger utilizes a switch which is alternately opened and closed by a multivibrator. When the switch is closed, the battery receives a charging current. When the switch is open, the battery voltage is sensed. If the sensed battery voltage exceeds a selected magnitude, the multivibrator is locked so that the switch remains open.

Claims

1. An improved battery-charging circuit comprising:

a. a first terminal for connection to a source of charging voltage;

b. a second terminal for connection to a battery to be charged;

c. switching means having a current path and having a control terminal for selectively opening and closing said current path;

d. means connecting said current path between said first and second terminals;

e. a pulse generator having first and second alternating states indicated at an output terminal;

f. means connecting said pulse generator output terminal to said switching means control terminal for opening said current path during said first state, and for closing said current path during said second state;

g. locking means connected to said second terminal and to said pulse generator output terminal and to said pulse generator output terminal for sensing the voltage at said second terminal during said first pulse generator state and producing a locking signal at an output terminal in response to a sensed voltage that exceeds a selected magnitude;

h. a means connecting said locking means output terminal to said pulse generator for locking said pulse generator in said first state in response to said locking signal, thereby maintaining said current path in an open condition.

2. The improved battery-charging circuit of claim 1, and further comprising a trickle-charging current impedance connected between said first and second terminals.

3. The improved battery-charging circuit of claim 1 wherein said locking means comprise a read switch connected to said second tErminal and controlled by said pulse generator, and comprise a voltage detector connected between said read switch and said pulse generator.

4. The improved battery-charging circuit of claim 1 wherein said second pulse generator state is longer than said first multivibrator state.

5. An improved battery-charging circuit comprising:

a. first and second source terminals for a charging current;

b. first and second output terminals for a battery to be charged;

c. means connecting said second source terminal to said second output terminal;

d. a current switch having a main path and a control terminal;

e. means connecting said main path between said first source terminal and said first output terminal;

f. a free-running multivibrator having first and second alternating states indicated at an output terminal;

g. means connecting said multivibrator output terminal to said current switch control terminal for closing said main path when said multivibrator is in said first state and for opening said main path when said multivibrator is in said second state;

h. a read switch having input and output terminals that are connected in response to a signal applied to a control terminal;

i. means connecting said read switch input terminal to said first output terminal and connecting said read switch control terminal to said multivibrator output terminal for connecting said read switch input and output terminals in response to said multivibrator being in said second state;

j. a voltage detector having an input terminal connected to said read switch output terminal and having an output terminal for producing a locking signal in response to a voltage that exceeds a selected magnitude at said voltage detector input terminal;

k. means connecting said voltage detector output terminal to said multivibrator for locking said multivibrator in said second state in response to said locking signal, and l. means connected to said multivibrator, for selectively unlocking said multivibrator.

6. The improved battery-charging circuit of claim 5, and further comprising a a trickle-charging current impedance connected between said first source terminal and said first output terminal.

7. The improved battery-charging circuit of claim 5, and further comprising a low voltage detector having an input terminal connected to said first output terminal and having an output terminal connected to said current switch control terminal for opening said main path when a voltage below a selected magnitude is detected.

8. The improved battery-charging circuit of claim 5 wherein said unlocking means comprise a high voltage detector having an input terminal connected to said first output terminal and having an output terminal connected to said multivibrator for unlocking said multivibrator after a high voltage has been detected.

9. The improved battery-charging circuit of claim 8, and further comprising a low voltage detector having an input terminal connected to said first output terminal and having an output terminal connected to said current switch control terminal for opening said main path when a voltage below a selected magnitude is detected.