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US 8,427,078 B2Granted
Light-emitting element driving device and display device
AssigneeSony Corporation
InventorsTakahiro Naito, Yasushi Katayama, Tatsuki Nishino
Life of this patent
Estimating the term…
Abstract
A light-emitting element driving device includes: a plurality of light emitters; a power supply; a plurality of current control transistors; a plurality of constant-current circuits; a voltage selecting circuit; a control circuit; and a voltage controller.
Claims10
A light-emitting element driving device comprising:
- a plurality of light emitters each including at least one light-emitting element for emitting light at a luminance level depending on a current flowing therethrough;
- a power supply for adjusting an output voltage depending on a signal supplied to a control terminal of a switch device and supplying the output voltage to ends of said light emitters;
- a plurality of current control transistors connected between respective other ends of said light emitters and a reference potential, said current control transistors being rendered conductive by respective energization signals;
- a plurality of constant-current circuits connected respectively in series to said current control transistors between the other ends of said light emitters and reference potential;
- a voltage selecting circuit for selecting a minimum voltage and a maximum voltage from junction terminal voltages between said current control transistors and said constant-current circuits;
- a control circuit for outputting a signal having a pulse duration depending on the minimum voltage selected by said voltage selecting circuit, to the control terminal of said switch device;
- and
- a voltage controller for generating a control voltage so as to make the maximum voltage selected by said voltage selecting circuit equal to or smaller than a preset maximum reference voltage and setting the level of said energization signals to the level of said control voltage.
5 more elements
A display device comprising:
- a transmissive display unit;
- an illumination unit for illuminating said transmissive display unit with emitted light, said illumination unit including a plurality of light emitters each including at least one light-emitting element for emitting light at a luminance level depending on a current flowing therethrough;
- and
- a light-emitting element driving device for driving the light-emitting elements of said light emitters,
- wherein said light-emitting element driving device includes
- a power supply for adjusting an output voltage depending on a signal supplied to a control terminal of a switch device and supplying the output voltage to ends of said light emitters,
- a plurality of current control transistors connected between respective other ends of said light emitters and a reference potential, said current control transistors being rendered conductive by respective energization signals,
- a plurality of constant-current circuits connected respectively in series to said current control transistors between the other ends of said light emitters and reference potential,
- a voltage selecting circuit for selecting a minimum voltage and a maximum voltage from junction terminal voltages between said current control transistors and said constant-current circuits,
- a control circuit for outputting a signal having a pulse duration depending on the minimum voltage selected by said voltage selecting circuit, to the control terminal of said switch device, and
- a voltage controller for generating a control voltage so as to make the maximum voltage selected by said voltage selecting circuit equal to or smaller than a preset maximum reference voltage and setting the level of said energization signals to the level of said control voltage.
8 more elements
Dependencies are inferred from the claim text.