초록 ▼

A battery charger includes charge control circuits each connected in parallel with an associated one of serially-connected battery cells. Each charge control circuit includes a switching device; a comparator, having a hysteresis characteristic determined by two threshold voltages, e.g., a safe charg

A battery charger includes charge control circuits each connected in parallel with an associated one of serially-connected battery cells. Each charge control circuit includes a switching device; a comparator, having a hysteresis characteristic determined by two threshold voltages, e.g., a safe charging voltage and an optimum charging voltage, for comparing the battery voltage with one of the threshold voltages selected according to a changing direction of the battery voltage; a reference voltage source for generating a reference voltage corresponding to either one of the threshold values; and a driving circuit for receiving a comparator output to render the switching device conductive or cutoff. When the battery voltage falls between the threshold voltages, the switching device becomes conductive to cause a constant current to flow from the battery cell to the switching device.

대표청구항 ▼

[ What is claimed is:] [1.] A battery charger comprising:a direct current power source adapted to be connected in series with a battery array which is comprised of serially-connected battery cells, said direct current power source being operable to output a predetermined maximum electric current whe

[ What is claimed is:] [1.] A battery charger comprising:a direct current power source adapted to be connected in series with a battery array which is comprised of serially-connected battery cells, said direct current power source being operable to output a predetermined maximum electric current when it performs a constant-current operation; andcharge control circuits adapted to be connected in parallel with the serially-connected battery cells, respectively, each of said charge control circuits including:a switching device which is connected in parallel with an associated one of the battery cells when said charge control circuit is connected to the associated one battery cell;a comparator, having a hysteresis characteristic thereof determined by a first threshold voltage and a second threshold voltage lower than the first threshold voltage, for comparing a battery voltage across the associated one battery cell with one of the first and second threshold voltages which is selected depending on a direction in which the battery voltage changes and for generating a comparator output indicative of a result of the comparison between the battery voltage and the selected one threshold voltage, the first and second threshold voltages being determined according to charging characteristics of the serially-connected battery cells;a reference voltage source for generating a reference voltage corresponding to one of the first and second threshold voltages; anda driving circuit for selectively rendering the switching device conductive according to the comparator output, said driving circuit being operable to permit a constant current to flow from the associated one battery cell to said switching device when said switching device is conductive.