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U.S. Department of Energy
Office of Scientific and Technical Information

Passive transformerless battery charging circuit

Patent ·
OSTI ID:7144376
A charging circuit is described for charging a low voltage battery from an AC supply voltage, the charging circuit comprising: input terminals adapted to be connected to the AC supply and output terminals adapted to be connected to an associated battery, first and second charging means, means capacitively coupling the first and second charging means to the input terminals. The first charging means includes means for providing to the battery at the output terminals a rectified relatively large charging current at a relatively low output voltage. The second charging means includes means for providing to the battery at the output terminals during alternate half cycles of the AC supply voltage a limited charging current at a relatively high output voltage. The first charging means includes control means for terminating the current flow from the first charging means to the output terminals when the voltage of the associated battery reaches a predetermined level.
Assignee:
Pittway Corp., Aurora, IL
Patent Number(s):
US 4621225
OSTI ID:
7144376
Country of Publication:
United States
Language:
English