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

Battery charging circuit

Patent ·
OSTI ID:6192741

A battery charging circuit having an electromagnetic transformer with primary and secondary coils, a rectifier connected between the secondary coil and the battery, a first transistor connected in series with the primary coil and a resistor to form a circuit in parallel with a power source, the base of the first transistor being connected to the secondary coil, and a second transistor electrically connected to the base of the first transistor. The first transistor has a high switching frequency, and the battery is charged with a constant reverse current during its blocking phase, regardless of the power source voltage. The first transistor is protected from reverse kick-back voltage pulses induced during its blocking phase by the provision of a diode and zener diode connected in series across the primary coil and a capacitor interposed between the secondary coil and the base of the first transistor.

Assignee:
Braun Ag (Germany, Federal Republic Of)
Patent Number(s):
US 4376263
OSTI ID:
6192741
Country of Publication:
United States
Language:
English