Light-emitting element driving device
First Claim
1. A light-emitting element driving device for driving a plurality of light-emitting element strings connected in parallel, the light-emitting element driving device comprising:
- a failure detector that monitors voltages at the plurality of light-emitting element strings, and detects a failure of each light-emitting element string of the plurality of light-emitting element strings;
a drive current controller that generates a plurality of drive current control signals; and
a plurality of drive current generators, each drive current generator of the plurality of drive current generators supplying a drive current to a corresponding one of the plurality of light-emitting element strings based on a corresponding one of the plurality of drive current control signals; and
a minimum detector that detects a minimum voltage of the voltages at the plurality of nodes and outputs a certain voltage which represents the minimum voltage, whereineach of the plurality of drive current generators independently adjusts a drive current of the corresponding one of the plurality of light-emitting element strings.
0 Assignments
0 Petitions
Accused Products
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.
11 Citations
19 Claims
-
1. A light-emitting element driving device for driving a plurality of light-emitting element strings connected in parallel, the light-emitting element driving device comprising:
-
a failure detector that monitors voltages at the plurality of light-emitting element strings, and detects a failure of each light-emitting element string of the plurality of light-emitting element strings; a drive current controller that generates a plurality of drive current control signals; and a plurality of drive current generators, each drive current generator of the plurality of drive current generators supplying a drive current to a corresponding one of the plurality of light-emitting element strings based on a corresponding one of the plurality of drive current control signals; and a minimum detector that detects a minimum voltage of the voltages at the plurality of nodes and outputs a certain voltage which represents the minimum voltage, wherein each of the plurality of drive current generators independently adjusts a drive current of the corresponding one of the plurality of light-emitting element strings. - View Dependent Claims (2, 3, 4, 5, 12, 14, 16, 18)
-
-
6. A light-emitting element driving device for driving a plurality of light-emitting element strings connected in parallel, the light-emitting element driving device comprising:
-
a drive current controller that generates a plurality of drive current control signals; and a plurality of drive current generators, each drive current generator of the plurality of drive current generators supplying a drive current to a corresponding one of the plurality of light-emitting element strings based on a corresponding one of the plurality of drive current control signals, wherein the light-emitting element driving device monitors voltages at each of the plurality of light-emitting element strings, and detects a failure of each light-emitting element string of the plurality of light-emitting element strings, each of the plurality of drive current generators independently adjusts a drive current of the corresponding one of the plurality of light-emitting element strings, and the light-emitting element driving device includes a minimum detector that detects a minimum voltage of the voltages at the plurality of nodes and outputs a certain voltage which represents the minimum voltage. - View Dependent Claims (7, 8, 9, 10, 11, 13, 15, 17, 19)
-
Specification