PURPOSE: To enable highly-precise detection of completion of charge by providing a comparator and a stepped-voltage generating means for detecting the completion of charge of an accumulator.
CONSTITUTION: Before the time point when an accumulator voltage Va lowers, a comparator 3 obtains a stepped voltage Vb corresponding to the voltage Va at the time of charging. A comparator 4 compares the voltage Va with Vb. A stepped-voltage generating circuit 6 connected 5 to the comparator 3 is composed of a binary counter 7 and a ladder-shaped DA converter circuit 8 and an output thereof is supplied top the comparator 4 through a voltage divider 9 and fed back to the comparator 3. According to this constitution, a pulse is obtained from the comparator 3 at a repetition frequency corresponding to a charging speed and the voltage Vb corresponding to the output pulse of the comparator 3 is generated by the circuit 6. Since this voltage Vb is higher than the voltage Va in an almost entire period, it is shifted below the voltage Va in the circuit 9. Each step of the voltage Vb is changed in one direction by the output pulse of the comparator 3, and therefore the step of the voltage Vb does not lower even when the voltage Va lowers. Accordingly, completion of charging can be known by detecting the crossing of the voltages Va and Vb by the comparator 4.
INOMATA RYUZO
IWATSUU SEIMITSU KK
AITETSUKU KK
| JPS63124729A | 1988-05-28 | |||
| JPS63213428A | 1988-09-06 |