Constant current source and battery charger
This patent describes a battery charger operated from a single-ended power supply. It comprises: pulse width modulation means including a transistor power switch, a diode and an inductor for supplying current to a battery; means for monitoring current flow to the battery; trigger means for controlling the frequency and duty cycle of the pulse width modulation means responsive to the monitoring means; a speed up circuit for the switch transistor comprising a shorting transistor coupled across the base-emitter circuit of the switch transistor and means responsive to the trigger means for driving the shorting transistor conductive; current foldback means including zener diode sensing means for monitoring the voltage of the battery; and means for changing the monitoring means to substantially reduce current flow to the battery when a battery voltage corresponding to a fully charged state is reached.
- Assignee:
- Zenith Electronics Corp., Glenview, IL
- Patent Number(s):
- A; US 4885522
- Application Number:
- PPN: US 7-272142A
- OSTI ID:
- 7012882
- Country of Publication:
- United States
- Language:
- English
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