Method and device for the modulation of the intensity of fluorescent lamps
First Claim
1. For use with a fluorescent lamp, an apparatus for adjusting the brightness of the lamp comprising:
- a power supply having an input for receiving an input voltage and a charging current;
a DC/AC converter coupled downstream of the power supply and having an output for delivering current to the lamp;
a switch in communication with the input of the power supply;
an electronic circuit responsive to a state change of the switch to cause a reduction in the input voltage if there is no flow of charging current to the power supply; and
a control circuit cooperating with the DC/AC converter in response to the reduction in the input voltage to control the current delivered to the lamp.
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Abstract
The invention describes a method for the modulation of the light intensity of fluorescent lamps via the supply main by modification of the form and/or the amplitude of the power supply provided. An electronic control element, provided as a component of the logical circuit, temporarily blocks current flow after at least every second zero-crossing of the voltage, dependent upon time and/or voltage. Blocking of the current flow occurs only during the time period in which there is no flow of charging current for the downstream direct-current mains supply circuit. The advantage thus obtained is that the control pulses for the logical circuit do not influence the electric current flowing through the fluorescent lamps.
46 Citations
29 Claims
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1. For use with a fluorescent lamp, an apparatus for adjusting the brightness of the lamp comprising:
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a power supply having an input for receiving an input voltage and a charging current;
a DC/AC converter coupled downstream of the power supply and having an output for delivering current to the lamp;
a switch in communication with the input of the power supply;
an electronic circuit responsive to a state change of the switch to cause a reduction in the input voltage if there is no flow of charging current to the power supply; and
a control circuit cooperating with the DC/AC converter in response to the reduction in the input voltage to control the current delivered to the lamp. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for adjusting a brightness of a fluorescent lamp, the apparatus comprising:
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a power supply having an input for receiving an input voltage;
a switch having a first state and a second state;
a logic circuit for altering the brightness of the fluorescent lamp in response to a reduction of the input voltage;
an electronic circuit for reducing the input voltage whenever;
(a) the switch is in the second state, and (b) no charging current is required by the power supply occur simultaneously; and
wherein the logic circuit does not alter the brightness in response to reductions in the input voltage with a duration below a predefined threshold duration. - View Dependent Claims (10, 11, 12)
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13. An apparatus for adjusting a brightness of a fluorescent lamp, the apparatus comprising:
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a power supply having an input for receiving an input voltage and a storage capacitor with an associated charging voltage;
a switch having a first state and a second state;
a logic circuit for altering the brightness of the fluorescent lamp in response to a reduction of the input voltage; and
an electronic circuit for reducing the input voltage whenever;
(a) the switch is in the second state, and (b) a momentary value of the input voltage is lower than the charging voltage of the storage capacitor.- View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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21. An apparatus for adjusting a brightness of a fluorescent lamp, the apparatus comprising:
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a power supply having an input for receiving an input voltage;
a switch having a first state and a second state;
a resistive impedance in parallel with the switch for reducing the input voltage when the switch is in the second state; and
a logic circuit in communication with the input for altering the brightness of the fluorescent lamp in response to a reduction of the input voltage;
wherein the logic circuit alters the brightness based upon a length of time that the input voltage is reduced.- View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29)
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Specification