Electricity: electrical systems and devices – Safety and protection of systems and devices – With specific current responsive fault sensor
Reexamination Certificate
1999-02-08
2001-04-03
Ballato, Josie (Department: 2836)
Electricity: electrical systems and devices
Safety and protection of systems and devices
With specific current responsive fault sensor
C361S093300, C323S284000, C323S288000
Reexamination Certificate
active
06212051
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to switching circuit current limiters, in particular, to current limiters used in combination with integrated circuit pulse-width modulator driver circuits.
BACKGROUND OF THE INVENTION
Prolonged short-circuit conditions of switching power supplies excessively stress the power components, resulting in premature and avoidable failure. Short circuit conditions are detected by a prolonged high level error amplifier output signal, which had been used to trigger a sequence of one-shot multi-vibrators to quench the operation of the pulse-width modulator driver circuit. Alternate embodiments count pulse periods after an overload or shorted condition is detected. Either implementation provides a fixed sequence of operation of serially operating or incrementing circuits. Such circuits also require a substantial number of components whose type and values make miniaturization and integration difficult if not impossible.
SUMMARY OF THE INVENTION
The pulse-width modulator (PWM) current limiter circuit according to the present invention is easily included with or appended to exiting PWM circuitry wherein the error amplifier output signal is used to initiate a driver shut-down, and to receive the signal that causes the driver shut-down. The error amplifier output signal is used to charge an RC circuit after which a comparitor provides an output signal coupled to the error amplifier output, causing it to be pulled to a state which inhibits the operation of the PWM driver. Simultaneously, the error amplifier output causes a change in topology so that a different R′C circuit is formed, and a different threshold (reference) voltage is provided so that a different and longer time period is provided during which the PWM driver operation is inhibited, after which the PWM driver is restarted for at least the durations provided by the first RC circuit.
REFERENCES:
patent: 4465966 (1984-08-01), Long et al.
patent: 4757433 (1988-07-01), Santelmann, Jr.
patent: 5892665 (1999-04-01), Matsumoto et al.
patent: 5903452 (1999-05-01), Yang
patent: 5910890 (1999-06-01), Hansen et al.
Acute Power, Inc.
Ballato Josie
Huyuh Kim
Matzuk Stephen G.
LandOfFree
Pulse-width modulator current limiter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pulse-width modulator current limiter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pulse-width modulator current limiter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2438482