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

Capacitor charging fet switcher with controller to adjust pulse width

Patent ·
OSTI ID:5747504

A switching power supply for charging a capacitive load is described which consists of: a step-up transformer having its secondary connected to the load; four power MOSFETs arrayed in a full bridge configuration connected to the primary of the step-up transformer; control means connected to the MOSFETs for alternately switching on and off diagonal pairs of the MOSFETs; soft start means connected to the control means for periodically adjusting pulse width to maintain approximate peak current to the load, the soft start means comprising a timing capacitor, parallel timing resistors of different values connected to the timing capacitor, and selection means for sequentially selecting one of the timing resistors for discharging the timing capacitor with a time constant determined by the value of the selected timing resistor.

Assignee:
Dept. of Energy, Washington, DC
Patent Number(s):
US 4586118
OSTI ID:
5747504
Country of Publication:
United States
Language:
English