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US 6,147,462 AGranted
Ballast
AssigneeVossloh-Schwabe Elektronik GmbH
InventorsRoland Sing, Gert Knobloch
Life of this patent
Estimating the term…
Abstract
In a ballast for parallel operation of discharge lamps in potentially explosive areas, an inverter is provided which has a branch which is assigned to the two discharge lamps, and in this respect is used twice. Two lamp-specific branches can be switched off separately if a fault occurs at the assigned discharge lamp.
Claims15
A ballast for parallel operation of discharge lamps, comprising:
- an inverter including a plurality of line branches, each line branch having a respective switching element controlled via a control input, at least two of the plurality of line branches being individually assigned to a respective one of the discharge lamps;
- a drive circuit which is connected to the control inputs of the switching elements and switches the switching elements on and off;
- and
- a monitoring circuit for monitoring the voltages of the discharge lamps independently of one another to determine whether a starting voltage is present across the discharge lamps for longer than a preset time interval, and if a voltage detected across one or more of the discharge lamps at an instant of time after a given ignition time overshoots an operating voltage of the one or more of the discharge lamps, blocking, via the drive circuit, the driving of only the switching elements arranged in line branches assigned to the one or more of the discharge lamps.
1 more element
Dependencies are inferred from the claim text.