Light emitting diode failure detection system for a vehicle with pre-trip inspection
First Claim
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1. A light failure detection system with pre-trip inspection for use in a vehicle having a plurality of light emitting diode lighting devices, said light failure detection system comprising:
- a circuit board;
a plurality of lighting circuits, each lighting circuit being coupled to the circuit board by an input wire;
a plurality of voltage level monitoring circuits on said circuit board, each one of said plurality of voltage level monitoring circuits connected to one of said lighting circuits and adapted to measure the voltage of the one of said light circuits;
a plurality of current monitoring circuits on said circuit board, each one of said plurality of current monitoring circuits connected to one of said lighting circuits and adapted to measure a current draw of the one of said light circuits;
a voltage drop circuit for enabling the plurality of voltage level monitoring circuits and the plurality of current monitoring circuits to measure current and voltage at an adjusted input voltage;
a temperature sensor for sensing a temperature;
a switch for placing the light failure detection system into a learn mode wherein said lighting circuits are monitored with the plurality of voltage level monitoring circuits and the plurality of current monitoring circuits to determine threshold voltage and current levels for the lighting circuits, the switch also adapted to activate a pre-trip inspection mode wherein said lighting circuits are sequentially activated to allow a user to inspect corresponding lighting units;
a microcontroller coupled to the circuit board for storing the threshold voltage and current levels and the temperature sensed by the temperature sensor, said microcontroller being adapted to calculate an adjusted threshold current based on a voltage sensitivity and the sensed temperature; and
a fault indicator for indicating a status of the light failure detection system is a measured current is above or below the adjusted threshold current by a predetermined value.
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Abstract
A light failure detection system with pre-trip inspection for use in a vehicle having a plurality of light emitting diode lighting devices includes a plurality of voltage level monitoring circuits and plurality of current monitoring circuits for measuring the voltage and current draw of a plurality of lighting circuits. The system includes a pre-trip inspection mode for sequentially activating a plurality of lighting circuits and allowing inspection of the plurality of light emitting diode lighting devices.
35 Citations
25 Claims
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1. A light failure detection system with pre-trip inspection for use in a vehicle having a plurality of light emitting diode lighting devices, said light failure detection system comprising:
- a circuit board;
a plurality of lighting circuits, each lighting circuit being coupled to the circuit board by an input wire;
a plurality of voltage level monitoring circuits on said circuit board, each one of said plurality of voltage level monitoring circuits connected to one of said lighting circuits and adapted to measure the voltage of the one of said light circuits;
a plurality of current monitoring circuits on said circuit board, each one of said plurality of current monitoring circuits connected to one of said lighting circuits and adapted to measure a current draw of the one of said light circuits;
a voltage drop circuit for enabling the plurality of voltage level monitoring circuits and the plurality of current monitoring circuits to measure current and voltage at an adjusted input voltage;
a temperature sensor for sensing a temperature;
a switch for placing the light failure detection system into a learn mode wherein said lighting circuits are monitored with the plurality of voltage level monitoring circuits and the plurality of current monitoring circuits to determine threshold voltage and current levels for the lighting circuits, the switch also adapted to activate a pre-trip inspection mode wherein said lighting circuits are sequentially activated to allow a user to inspect corresponding lighting units;
a microcontroller coupled to the circuit board for storing the threshold voltage and current levels and the temperature sensed by the temperature sensor, said microcontroller being adapted to calculate an adjusted threshold current based on a voltage sensitivity and the sensed temperature; and
a fault indicator for indicating a status of the light failure detection system is a measured current is above or below the adjusted threshold current by a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6)
- a circuit board;
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7. A method of detecting a failure of a light emitting diode lighting device in a vehicle having a failure detection system, said method comprising:
- activating a pre-trip inspection mode;
sequentially activating a plurality of lighting circuits to allow a user to inspect corresponding lighting units;
activating a learn mode;
measuring a current (C_ref) and a voltage (V_ref) of a plurality of lighting circuits at an input voltage;
measuring a system temperature (T_ref);
deactivating said learn mode;
measuring at least one light drive input current (C_now) and voltage (V_now) in a normal mode;
measuring the system temperature in a normal mode;
calculating an adjusted threshold current value based on a voltage sensitivity and system temperature;
determining if the measured light drive input current is below or above the adjusted threshold current value by a predetermined value; and
displaying an indication of light failure if the measured current is below or above the adjusted threshold current value by said predetermined value. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
- activating a pre-trip inspection mode;
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16. A method of detecting a failure of a light emitting diode lighting device in a vehicle having a failure detection system, said method comprising:
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activating a pre-trip inspection mode by sequentially activating a plurality of lighting circuits to allow a user to inspect corresponding lighting units, said lighting circuits coupled to a circuit board by one or more input wires; activating a switch to thereby place said light failure detection system into a learn mode; measuring a current (C_ref) via a one or more current monitoring circuits and a voltage (V_ref) via one or more voltage monitoring circuits of the plurality of lighting circuits at an input voltage; measuring a system temperature (T_ref) via a temperature sensor; deactivating said learn mode by use of the; measuring at least one light drive input current (C_now) and voltage (V_now) in a normal mode; measuring the system temperature in a normal mode; a microcontroller calculating an adjusted threshold current value based on a voltage sensitivity and system temperature, wherein said microcontroller stores threshold voltage and current levels and the temperature sensed by the temperature sensor; determining if the measured light drive input current is below or above the adjusted threshold current value by a predetermined value; and displaying an indication of light failure if the measured current is below or above the adjusted threshold current value by said predetermined value. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification