US 2016/0097822 A1 · SINGLE LED FAILURE DETECTION IN A LED CHAIN

Abstract

Methods and circuits are described in which an SLS driver circuit includes an SLS driver current source that may be arranged to provide an SLS current to a series SLS chain at a series SLS node. The series SLS chain may include a plurality of SLSs connected in series. The SLS driver circuit also includes a diagnostic current source that is arranged to provide a diagnostic current to a diagnostic resistor at a diagnostic resistor node. The series SLS chain also includes a comparison circuit that may be arranged to compare a series SLS voltage at the series SLS node with a diagnostic voltage at the diagnostic resistor node, and to output a status signal based on a result of the comparison such that the status signal is based, at least in part, on whether a failure condition exists in the series SLS chain.

Claims20

Dependent claims

A device, comprising:

a semiconductor light source (SLS) driver circuit, including:
an SLS driver current source that is arranged to provide an SLS current to a series SLS chain at a series SLS node, wherein the series SLS chain includes a plurality of SLSs connected in series;
a diagnostic current source that is arranged to provide a diagnostic current to a diagnostic resistor at a diagnostic resistor node;
and
a comparison circuit that is arranged to perform a comparison to compare a series SLS voltage at the series SLS node with a diagnostic voltage at the diagnostic resistor node, and to output a status signal based on a result of at least the comparison such that the status signal is based, at least in part, on whether a failure condition exists in the series SLS chain.

2 more elements

A method, comprising:

providing an LED current to a series LED chain at a series LED node, wherein the series LED chain includes a plurality of LEDs connected in series;
providing a diagnostic current to a diagnostic resistor at a diagnostic resistor node;
performing a comparison to compare a series LED voltage at the series LED node with a diagnostic voltage at the diagnostic resistor node;
and
outputting a status signal based on a result of the comparison such that the status signal is based, at least in part, on whether a failure condition exists in the series LED chain.

2 more elements

Dependencies are inferred from the claim text.

Single led failure detection in a led chain

Life of this patent

Single led failure detection in a led chain

Life of this patent

Abstract

Claims20