Quick charging circuit

Claim 1

A quick charging circuit comprising: a charging current generating circuit including a rectifier connected to an A.C. power source and a high frequency invertor connected to said rectifier for supplying a charging current to a storage battery wherein said high frequency invertor includes a first switching transistor connected at the collector to the primary winding of a transformer connected at the secondary winding to said storage battery, and a second switching transistor for bypassing a base current which biases said first switching transistor and reducing said charging current; a circuit for detecting a voltage across said battery including a detecting IC circuit which generates a low level output upon detection of a predetermined voltage; an integrating circuit provided with respect to said battery voltage detecting circuit for restraining any influence of high frequency components in said battery voltage wherein said integrating circuit is connected to a third transistor which is turned OFF with an output lower than a set level in response to said low level output of said detecting IC circuit and wherein said integrating circuit is connected after said battery voltage detecting circuit; and a timer circuit operated by an output of said battery voltage detecting circuit wherein said timer circuit has an input terminal connected to the collector of said third transistor, is actuated upon a high level at said input terminal, and provides after a predetermined time elapsed, an output for biassing said second switching transistor thereby controlling a base current biassing said first switching transistor and reducing said charging current, and wherein said timer circuit is connected after said integrating circuit.