LED aviation warning light with fault detection
First Claim
1. An LED warning light comprising:
- at least one group of LED lamps arranged to collectively produce an illumination pattern having an intensity exceeding predetermined values over a specified angular distribution, said at least one group of LED lamps divided into a plurality of LED banks, each LED bank comprising a plurality of LED lamps connected in series, said LED lamps having a luminance which is a function of a current applied to the LED lamp;
a plurality of bank driver circuits, each bank driver circuit operatively connected to deliver current to one of said LED banks, each bank driver circuit sensing current flow through the LED bank to which it is connected and producing a fault output indicating failure of the LED bank, each said bank driver circuit responsive to an input signal to vary the current applied to the LED bank; and
a controller operatively configured to receive said fault outputs and provide a first input signal to all said bank driver circuits corresponding to a first current in the absence of a fault output and a second input signal to all said bank driver circuits corresponding to a second current when a fault output is present,wherein said second current is selected to increase the luminance of the LED lamps in the LED banks other than said failed LED bank to compensate for the loss of luminance from the LED lamps in the failed LED bank.
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Accused Products
Abstract
An embodiment of an LED warning light includes a plurality of LED banks, each including a series of light emitting diodes. The LED warning light monitors an operational parameter of each LED bank to detect failure of an LED and produce a fault indication. The LED warning light includes a microcontroller programmed to evaluate the fault indications and take one or more pre-determined failure mode actions. Failure detection and failure mode actions are defined by program steps taken by firmware running in the microcontroller. Failure mode actions may include increasing the current delivered to remaining LED banks to compensate for the loss of luminance from the LEDs in a failed LED bank. Multiple bank failures may require shutting down the LED warning light to provide an obvious indication that the warning light is no longer in compliance with relevant regulations.
75 Citations
18 Claims
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1. An LED warning light comprising:
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at least one group of LED lamps arranged to collectively produce an illumination pattern having an intensity exceeding predetermined values over a specified angular distribution, said at least one group of LED lamps divided into a plurality of LED banks, each LED bank comprising a plurality of LED lamps connected in series, said LED lamps having a luminance which is a function of a current applied to the LED lamp; a plurality of bank driver circuits, each bank driver circuit operatively connected to deliver current to one of said LED banks, each bank driver circuit sensing current flow through the LED bank to which it is connected and producing a fault output indicating failure of the LED bank, each said bank driver circuit responsive to an input signal to vary the current applied to the LED bank; and a controller operatively configured to receive said fault outputs and provide a first input signal to all said bank driver circuits corresponding to a first current in the absence of a fault output and a second input signal to all said bank driver circuits corresponding to a second current when a fault output is present, wherein said second current is selected to increase the luminance of the LED lamps in the LED banks other than said failed LED bank to compensate for the loss of luminance from the LED lamps in the failed LED bank. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An LED warning light comprising:
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a plurality of light-emitting diodes (LEDs) arranged in two or more groups of LEDs, each group of LEDs configured to emit a pattern of light having a predetermined intensity and distribution, each group of LEDs including a plurality of LED banks, each LED bank comprising a plurality of LEDs connected in series, said LEDs having a luminance which is a function of applied current; a plurality of bank drivers, each bank driver connected to deliver current to one of said LED banks, each bank driver producing a fault output indicating failure of the LED bank to which it is connected and responsive to an input signal to vary the current applied to the LED bank; a controller configured to apply a first applied current to said bank drivers in the absence of a fault output and a second applied current to the bank drivers of a group of LEDs that is the source of a fault output, wherein said second applied current is selected to increase the luminance of the LEDs in the LED banks in the group including a failed LED bank to compensate for the loss of luminance from the LEDs in the failed LED bank. - View Dependent Claims (9, 10, 11, 12, 13)
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14. An LED warning light comprising:
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two or more groups of LEDs, each group of LEDs including a plurality of LED banks, each LED bank comprising; a plurality of LEDs connected in series; and a bank driver circuit arranged to deliver current to said plurality of LEDs, said current being variable according to the duty cycle of a PWM input signal, monitor one or more operational parameter of said plurality of LEDs and produce a fault output when said one or more operational parameter indicates failure of at least one LED in said plurality of LEDs; a controller operatively connected to generate the PWM input signal to said bank drivers and receive said fault outputs, said controller configured to increase the current applied to the LEDs in the LED banks in a group of LEDs that is the source of a fault output by altering the duty cycle of the input signal delivered to bank driver circuits in the group of LEDs that is the source of a fault output. - View Dependent Claims (15, 16, 17, 18)
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Specification