skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Capacitor charging FET switcher with controller to adjust pulse width

Abstract

A switching power supply includes an FET full bridge, a controller to drive the FETs, a programmable controller to dynamically control final output current by adjusting pulse width, and a variety of protective systems, including an overcurrent latch for current control. Power MOSFETS are switched at a variable frequency from 20-50 kHz to charge a capacitor load from 0 to 6 kV. A ferrite transformer steps up the DC input. The transformer primary is a full bridge configuration with the FET switches and the secondary is fed into a high voltage full wave rectifier whose output is connected directly to the energy storage capacitor. The peak current is held constant by varying the pulse width using predetermined timing resistors and counting pulses. The pulse width is increased as the capacitor charges to maintain peak current. A digital ripple counter counts pulses, and after the desired number is reached, an up-counter is clocked. The up-counter output is decoded to choose among different resistors used to discharge a timing capacitor, thereby determining the pulse width. A current latch shuts down the supply on overcurrent due to either excessive pulse width causing transformer saturation or a major bridge fault, i.e., FET or transformermore » failure, or failure of the drive circuitry.« less

Inventors:
 [1]
  1. Livermore, CA
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
865832
Patent Number(s):
US 4586118
Assignee:
United States of America as represented by United States (Washington, DC)
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
capacitor; charging; fet; switcher; controller; adjust; pulse; width; switching; power; supply; bridge; drive; fets; programmable; dynamically; control; final; output; current; adjusting; variety; protective; systems; including; overcurrent; latch; mosfets; switched; variable; frequency; 20-50; khz; charge; load; kv; ferrite; transformer; steps; dc; input; primary; configuration; switches; secondary; fed; voltage; wave; rectifier; connected; directly; energy; storage; peak; held; constant; varying; predetermined; timing; resistors; counting; pulses; increased; charges; maintain; digital; ripple; counter; counts; desired; reached; up-counter; clocked; decoded; choose; discharge; determining; shuts; due; excessive; causing; saturation; major; fault; failure; circuitry; peak current; connected directly; dc input; output current; storage capacitor; variable frequency; pulse width; energy storage; power supply; drive circuit; wave rectifier; timing capacitor; switching power; programmable control; final output; counter counts; drive circuitry; current control; held constant; programmable controller; /363/

Citation Formats

Mihalka, Alex M. Capacitor charging FET switcher with controller to adjust pulse width. United States: N. p., 1986. Web.
Mihalka, Alex M. Capacitor charging FET switcher with controller to adjust pulse width. United States.
Mihalka, Alex M. Wed . "Capacitor charging FET switcher with controller to adjust pulse width". United States. https://www.osti.gov/servlets/purl/865832.
@article{osti_865832,
title = {Capacitor charging FET switcher with controller to adjust pulse width},
author = {Mihalka, Alex M},
abstractNote = {A switching power supply includes an FET full bridge, a controller to drive the FETs, a programmable controller to dynamically control final output current by adjusting pulse width, and a variety of protective systems, including an overcurrent latch for current control. Power MOSFETS are switched at a variable frequency from 20-50 kHz to charge a capacitor load from 0 to 6 kV. A ferrite transformer steps up the DC input. The transformer primary is a full bridge configuration with the FET switches and the secondary is fed into a high voltage full wave rectifier whose output is connected directly to the energy storage capacitor. The peak current is held constant by varying the pulse width using predetermined timing resistors and counting pulses. The pulse width is increased as the capacitor charges to maintain peak current. A digital ripple counter counts pulses, and after the desired number is reached, an up-counter is clocked. The up-counter output is decoded to choose among different resistors used to discharge a timing capacitor, thereby determining the pulse width. A current latch shuts down the supply on overcurrent due to either excessive pulse width causing transformer saturation or a major bridge fault, i.e., FET or transformer failure, or failure of the drive circuitry.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1986},
month = {1}
}

Patent:

Save / Share: