Charging system

• US 4,021,717 A
• Filed: 03/17/1975
• Issued: 05/03/1977
• Est. Priority Date: 05/16/1973
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Furuishi, Haruhisa, Kawamoto, Katsuaki, Koyama, Yoneji
• Primary Examiner(s): Hickey, Robert J.
• Application Number:
  US05/559,214
• Time in Patent Office: 778 Days
• Field of Search: 321/2, 321/18, 320/2, 320/54, 320/56, 320/39, 320/40, 320/21-24
• US Class Current: 320/140
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: Y10S 320/25 Optical coupler

Abstract

There is provided a charging system for secondary batteries comprising a high-frequency power supply circuit consisting of a transistor DC-DC converter and a control circuit for preventing the overcharging of a battery to be charged, whereby the oscillation of the high-frequency power supply circuit is controlled by the control circuit. Thus, the size and weight of the charging system of this invention are reduced.

Claims

1. A system for charging a storage battery comprising:

(a) a high-frequency power supply circuit including a DC-DC converter, said DC-DC converter comprising an oscillatory circuit having an output transistor, a transformer having its primary winding connected to the output of said output transistor, and a rectifier, said circuit supplying pulse current from the secondary winding of said transformer to said storage battery through said rectifier;

(b) a voltage switching circuit for detecting the voltage across said storage battery comprising a plurality of voltage dividing resistors connected across said storage battery;

a first transistor having its base connected to a junction between two of said plurality of voltage dividing resistors;

first resistor means coupling the emitter and collector of said first transistor across said storage battery;

a second transistor having its base connected to the collector of said first transistor, said second transistor being of the opposite conduction type from said first transistor;

second resistor means coupling the emitter and collector of said second transistor across said storage battery;

a resistor coupled between the emitters of said first and second transistors; and

at least one amplifying transistor for amplifying the output of said second transistor, said voltage switching circuit detecting the voltage across said storage battery and being switched from its OFF state to its ON state when the voltage across said storage battery rises to a preset value; and

(c) a feedback circuit coupling the last stage amplifying transistor of said voltage switching circuit across the base and emitter of said output transistor, said feedback circuit causing said high-frequency power supply circuit to stop oscillating in response to the turn-on of said voltage switching circuit.

2. A charging system according to claim 1, wherein a pilot lamp and a rectifier are connected in series across the secondary winding of said transformer, said rectifier being rendered conductive in a phase opposite to that of the charging current.