LED turn signal and error detecting method

A method for detecting a failure of a light emitting diode in a motor vehicle turn signal assembly comprising a plurality of light emitting diodes, the method comprising the steps of:

• selectively sourcing a current to the plurality of light emitting diodes in response to activation of a turn signal switch;
• detecting a failure of one of the plurality of light emitting diodes at an error detecting unit located in proximity to the motor vehicle turn signal assembly;
• activating a current sinking element to cause a measurable change in the current sourced to the plurality of light emitting diodes in response to the error detecting unit detecting a failure in one of the plurality of light emitting diodes;
• detecting the measurable change in the current sourced to the plurality of light emitting diodes at a location remote from the plurality of light emitting diodes;
• and
• activating a failure indicator.

A method for detecting a failure of a light emitting diode in a motor vehicle turn signal assembly comprising a plurality of light emitting diodes, the method comprising the steps of:

• arraying the plurality of light emitting diodes in a plurality of parallel coupled banks of series connected light emitting diodes;
• supplying turn signal current to the plurality of banks of light emitting diodes in response to activation of a turn signal switch;
• measuring a turn signal bank current in each of the plurality of banks of light emitting diodes;
• detecting a change exceeding a predetermined amount in the turn signal bank current supplied to one of the plurality of banks of light emitting diodes in response to an error in one of the plurality of light emitting diodes;
• activating a current sink in response to the step of detecting a change, the current sink coupled to cause a measurable change in the turn signal current;
• and
• detecting the measurable change in the turn signal current.

A motor vehicle turn signal comprising:

• a front turn signal element;
• a rear turn signal assembly comprising a plurality of light emitting diodes coupled in a plurality of parallel banks of series coupled light emitting diodes, the rear turn signal assembly coupled in parallel to the front turn signal element;
• a power source coupled to supply current to the front turn signal element and the rear turn signal assembly in parallel;
• a first detector coupled to the power source and configured to detect a change in the current supplied by the power source;
• a second detector coupled to each of the parallel banks of light emitting diodes and configured to detect a malfunction in one of the light emitting diodes;
• a current sink coupled to the second detector and to the power source and configured, in response to the second detector detecting a malfunction, to cause a sufficient change in the current supplied by the power source to be detectable by the first detector.

A motor vehicle turn signal assembly comprising:

• a plurality of parallel banks of series coupled light emitting diodes;
• a power source selectively supplying current to the plurality of banks;
• a comparator circuit coupled to each of the plurality of banks and configured to provide an error signal in response to a current in one of the plurality of banks being outside a predetermined range;
• and
• a current sink coupled to the power source and configured to activate in response to reception of the error signal to cause a change in state of the power source.