Circuit arrangement and method for operating discharge lamps
AssigneeOsram Gesellschaft Mit Beschraenkter Haftung
InventorsAlois Braun, Walter Limmer, Maximilian Schmidl
Life of this patent
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Abstract
A circuit arrangement for operating discharge lamps is provided with an input, to which an AC system voltage from a power supply system can be connected, an output, to which at least one discharge lamp can be connected, a backup capacitance, which is arranged between the input and the output, and a switch, which is in a charging current path of the backup capacitance. The circuit arrangement may include a driver configured to clock the switch for a predetermined period of time when the circuit arrangement is switched on for periodically interrupting the charging current path of the backup capacitance.
Claims15
A circuit arrangement for operating discharge lamps with an input, to which an AC system voltage from a power supply system can be connected, an output, to which at least one discharge lamp can be connected, a backup capacitance, which is arranged between the input and the output, and a switch, which is in a charging current path of the backup capacitance, the circuit arrangement comprising:
- a driver configured to clock the switch for a predetermined period of time when the circuit arrangement is switched on for periodically interrupting the charging current path of the backup capacitance,
- wherein the driver configured to clock the switch in system-synchronous fashion, the circuit arrangement being configured to switch on the switch temporarily in each case at a zero crossing of an applied system voltage, and switching off said switch again prior to a subsequent peak voltage of the system voltage.
A method for operating discharge lamps, with a circuit arrangement for implementing the method, the circuit arrangement comprising an input, to which an AC system voltage from a power supply system can be connected, and an output, to which at least one discharge lamp can be connected, and a backup capacitance, which is arranged between the input and output, and a switch which is in a charging current path of the backup capacitance, the method comprising the following processes which are repeated a plurality of times:
- detecting a voltage zero crossing of an AC system voltage present at the input;
- switching-on the switch;
- testing whether a predetermined switch-on time span of the switch has been reached, or testing whether the voltage present across the backup capacitance has risen by a predetermined value;
- if so then to the next process;
- and testing whether the voltage present across the backup capacitance has reached a predetermined value, if no then switching-off of the switch, and if yes then conclusion of the method.
Dependencies are inferred from the claim text.