Detecting circuit for battery voltage

Abstract

Abstract PURPOSE:To decide the extent of necessity of battery replacement and whether a backup is secured or not by comparing a battery voltage with two threshold values and displaying its large/small relation. CONSTITUTION:The voltage of a battery 5 is inputted to comparators 1 and 2 having the threshold values V1 and V2 respectively and the emitter of a transistor (TR) 3 is connected to a light emitting diode 4 for low voltage detection display through a resistance R5. When the voltage E of the battery 5 is higher than the V1, the comparators 1 and 2 output 0 and 0 respectively and the TR 3 becomes cutoff to turn off the light emitting diode 4, indicating that the voltage is normal. When V1>E>V2, on the other hand, the comparators 1 and 2 output 1 and 0 and the light emitting diode 4 illuminates with low brightness, indicating memory contents are secured by speedy battery replacement. When V2>E, the comparators 1 and 2 output 1 and 1 and the light emitting diode 4 illuminates with high brightness, stating that the battery is discharged completely and the memory contents are not secured.

Inventors

• 👤 Kenji Tokunaga
• 👤 徳永　賢治

Bibliographic Details