| US 7,579,807 B2 | ||
| Battery charger | ||
| Kazuhiko Funabashi, Ibaraki (Japan); Nobuhiro Takano, Ibaraki (Japan); Kenro Ishimaru, Ibaraki (Japan); and Takao Aradachi, Ibaraki (Japan) | ||
| Assigned to Hitachi Koki Co., Ltd., Tokyo (Japan) | ||
| Filed on Mar. 09, 2006, as Appl. No. 11/370,944. | ||
| Claims priority of application No. P 2005-068367 (JP), filed on Mar. 11, 2005. | ||
| Prior Publication US 2006/0208699 A1, Sep. 21, 2006 | ||
| Int. Cl. H02J 7/00 (2006.01) | ||
| U.S. Cl. 320—106 [320/114; 320/122; 320/137] | 21 Claims |
| 1. A battery charger comprising:
an Alternating Current (AC) power supply;
a first rectifier smoothing circuit for rectifying and smoothing the AC voltage;
a switching circuit connected across output terminals of the first rectifier smoothing circuit to provide pulse signals;
a second rectifier smoothing circuit for rectifying and smoothing the pulse signals, an output voltage of the second rectifier
smoothing circuit being applied to a battery to be charged;
a charging current control unit that detects a charging current flowing through the battery and controls the charging current
in accordance with a charging current set value;
trigger means connected across the battery to be charged for generating a first trigger voltage based on a residual voltage
of the battery when the battery is connected to the charger;
constant voltage generating means connected to the trigger means to receive the first trigger voltage and adapted to generate
a constant voltage which is applied to the charging current control unit as an operating voltage thereof; and
a microcomputer that detects if the battery is connected to the charger and applies a control signal to the constant voltage
generating means to stop supplying the operation voltage to the charging current control unit when the battery is detached
from the battery charge.
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