BATTERY CHARGING SYSTEM HAVING LOGARITHMIC ANALOG-TO-DIGITAL CONVERTER WITH AUTOMATIC SCALING OF ANALOG SIGNAL

摘要

An ultra-quick charging device for charging battery packs having a wide range of output voltages. The charging device includes an AC to DC high current power supply circuit and a microcomputer-based controller circuit for monitoring the voltage of the battery and converting from fast charge to trickle charge when the second inflection point in the battery voltage charge curve is detected. In order to permit the device to charge battery packs of different rated voltages, the device includes a logarithmic analog-to-digital converter circuit having a selectable prescaler circuit that attenuates the battery voltage signal. The microcomputer is programmed to automatically set the appropriate attenuation level of the prescaler circuit at the outset of the charging cycle by assuming that the maximum voltage of the battery pack being charged will be less than or equal to 150 percent of its observed battery voltage. The present invention is able to automatically fully charge battery packs ranging in voltage between 3 volts and 24 volts.