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US 2003/0117089 A1Published application
Driving serially connected high intensity discharge lamps
AssigneeMicrolights Limited
InventorLawrence Samuel Tyson
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AssigneeMicrolights Limited
InventorLawrence Samuel Tyson
Estimating the term…
A lighting system (1) comprises a plurality of high intensity discharge lamps (9, 39, 6) and an electronic control (2) having a power input (4), an alternating current power output regulator (22), and an alternating power output (3) having an output frequency arranged to be variable within an output frequency range, the output having a first and a second output line. The lamps are connected in series with each other so that the first line is connected to the first electrode (11) of the first of the lamps, the second electrode (12) of the first of the lamps is connected to the first electrode (41) of the next lamp in the series, the second electrode (13) of the final lamp in the series being connected to the second output line. The lamps have an acoustic resonant frequency range and the output frequency range of the control is arranged to be above the acoustic resonant frequency range.
A lighting system comprising at least:
A lighting system as claimed in any one of the preceding claims wherein a resistor is connected in parallel with each lamp.
A lighting system as claimed in any one of the preceding claims wherein the control is arranged to monitor a mid-point voltage level between an adjacent pair of lamps.
A lighting system as claimed in any of the preceding claims wherein the regulated alternating current power output for powering the lamps has an output frequency greater than a frequency of a power supply to the ballast.
A lighting system as claimed in any of the preceding claims wherein the control has a direct current to alternating current converter producing the regulated alternating current power output for powering the lamps, the control having an output frequency range greater 300 kHz.
A lighting system as claimed in any of the preceding claims wherein the output frequency range is above 400 kHz.
A lighting system as claimed in any of the preceding claims wherein the output frequency range is entirely above the upper limit frequency of the acoustic resonant frequency range of the lamps.
A lighting system as claimed in any of the preceding claims wherein the alternating current output has a sinusoidal waveform.
Dependencies are inferred from the claim text.