Failure Detection for Series of Electrical Loads
First Claim
1. An apparatus for detecting failures in an illumination device comprising at least two light emitting diodes connected in series, the apparatus comprising:
- a first circuit node, a second circuit node, and a third circuit node for interfacing the illumination device such that a voltage drop across the at least two light emitting diodes is applied between the first and the second circuit node and a fraction of the voltage drop is applied between the second and the third circuit node; and
an evaluation unit coupled to the first, the second, and the third circuit node and configured to assess whether an electric potential present at the third circuit node is within a pre-defined range of tolerance about a nominal value that is defined as a pre-defined fraction of the voltage drop present between the first and the second circuit node.
1 Assignment
0 Petitions
Accused Products
Abstract
An apparatus for detecting failures in an illumination device includes at least two light emitting diodes connected in series. The apparatus includes a first, a second, and a third circuit node for interfacing the illumination device such that the voltage drop across at least two light emitting diodes is applied between the first and the second circuit node and a fraction of the voltage drop is applied between the second and the third circuit node. An evaluation unit is coupled to the first, the second, and the third circuit node and configured to assess whether the electric potential present at the third circuit node is within a pre-defined range of tolerance about a nominal value that is defined as a pre-defined fraction of the potential difference present between the first and the second circuit node.
25 Citations
20 Claims
-
1. An apparatus for detecting failures in an illumination device comprising at least two light emitting diodes connected in series, the apparatus comprising:
-
a first circuit node, a second circuit node, and a third circuit node for interfacing the illumination device such that a voltage drop across the at least two light emitting diodes is applied between the first and the second circuit node and a fraction of the voltage drop is applied between the second and the third circuit node; and an evaluation unit coupled to the first, the second, and the third circuit node and configured to assess whether an electric potential present at the third circuit node is within a pre-defined range of tolerance about a nominal value that is defined as a pre-defined fraction of the voltage drop present between the first and the second circuit node. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
-
-
14. An illumination device comprising:
-
a plurality of light emitting diodes connected in series; a plurality of resistors connected in series, the series connected plurality of resistors being coupled in parallel with the series connected plurality of light emitting diodes; and a comparator circuit with a first input coupled to a first intermediate point between ones of the series connected light emitting diodes and a second input coupled to a second intermediate point between ones of the series connected resistors. - View Dependent Claims (15, 16, 17)
-
-
18. A method for detecting failures in an illumination device comprising a plurality of light emitting diodes, the method comprising:
-
sensing a voltage drop across the light emitting diodes; sensing a fraction of the voltage drop across the light emitting diodes at an intermediate tap of a series circuit of light emitting diodes; and assessing whether the sensed fraction is within a pre-defined range of tolerance about a nominal value that is defined as a pre-defined fraction of the sensed voltage drop. - View Dependent Claims (19, 20)
-
Specification