US 2012/0074856 A1 · LIGHT-EMITTING ELEMENT DRIVING DEVICE

Abstract

Short circuit failures and open circuit failures of light-emitting elements used for the backlight in an LCD panel can be reliably and easily detected. The voltage at the node between each series-connected light-emitting element array and a drive circuit is detected as a monitored voltage. A maximum detector detects the highest and a minimum detector detects the lowest of these monitored voltages. Short circuit or open circuit failure of a light-emitting element is detected by comparing the voltage difference between the maximum detector output and the minimum detector output with a specific reference voltage.

Claims26

Dependent claims

A light-emitting element driving device comprising:

a light-emitting element load group having a plurality of parallel-connected light-emitting element arrays each having more than one light-emitting elements connected in series;
a supply voltage converter that converts a supply voltage and supplies a specific output voltage to the light-emitting element load group;
a drive circuit that supplies a load current for driving a light-emitting element connected in series in the light-emitting element array;
a power controller that generates a control signal for the supply voltage converter;
and
a failure detector that detects failure of the light-emitting element,
wherein the failure detector monitors the potential of a node between the light-emitting element array and the drive circuit, or a voltage based on this node potential, as a monitored voltage, and detects failure of a light-emitting element based on the monitored voltages of at least two light-emitting element arrays.

4 more elements

Dependencies are inferred from the claim text.

Light-emitting element driving device

Life of this patent

Light-emitting element driving device

Life of this patent

Abstract

Claims26