US 2010/0060674 A1Published application

Light-emitting element driving circuit

AssigneesSanyo Electric Co., Ltd., Sanyo Semiconductor Co., Ltd.

InventorsTomoshi Yoshida, Nobuyuki Ohtaka

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Abstract

A light-emitting element driving circuit (10) comprises a luminosity determining unit (70) which determines luminosity, outputs a luminosity determination result, and outputs brightness change information, a brightness setting unit (60) which outputs brightness setting information and outputs brightness change information, a light-emitting element driving unit (40) which drives a light-emitting element with a current of a current value corresponding to the brightness setting information, a detecting and comparing unit (50) which compares a terminal voltage of the light-emitting element and a predetermined voltage, a voltage boost determining unit (30) which determines whether or not a terminal voltage of the light-emitting element is to be boosted based on at least one of the luminosity change information and the brightness change information, and a voltage boosting circuit section (20) which boosts the terminal voltage of the light-emitting element when it is determined that the voltage is to be boosted and does not boost the terminal voltage of the light-emitting element when it is determined that the voltage is not to be boosted.

Claims10

Dependent claims

A light-emitting element driving circuit comprising:

a luminosity determining unit which acquires luminance information from a luminance sensor, determines luminosity, outputs a luminosity determination result, and outputs luminosity change information;
a brightness setting unit which sets brightness based on the luminosity determination result of the luminosity determining unit, outputs brightness setting information, and outputs brightness change information;
a light-emitting element driving unit which drives a light-emitting element with a current of a current value corresponding to the brightness setting information from the brightness setting unit;
a detecting and comparing unit which detects a terminal voltage of a first terminal of the light-emitting element and compares with a predetermined voltage;
a voltage boost determining unit which determines whether or not a terminal voltage of a second terminal of the light-emitting element is to be boosted based on at least one of the luminosity change information and the brightness change information, and an output of the detecting and comparing unit;
and
a voltage boosting circuit section which boosts the terminal voltage of the second terminal of the light-emitting element when the voltage boost determining unit determines that the voltage is to be boosted and which does not boost the terminal voltage of the second terminal of the light-emitting element when the voltage boost determining unit determines that the voltage is not to be boosted.

4 more elements

A light-emitting element driving circuit comprising:

a light emission mode setting unit which sets a light emission mode of a light-emitting element based on a light emission mode signal from a central processing unit, outputs light emission mode setting information, and outputs light emission mode change information;
a light-emitting element driving unit which drives the light-emitting element with a current of a current value corresponding to the light emission mode setting information from the light emission mode setting unit;
a detecting and comparing unit which detects a terminal voltage of a first terminal of the light-emitting element and compares with a predetermined voltage;
a voltage boost determining unit which determines whether or not a terminal voltage of a second terminal of the light-emitting element is to be boosted based on the light emission mode change information and an output of the detecting and comparing unit;
and
a voltage boosting circuit section which boosts the terminal voltage of the second terminal of the light-emitting element when the voltage boost determining unit determines that the voltage is to be boosted and which does not boost the terminal voltage of the second terminal of the light-emitting element when the voltage boost determining unit determines that the voltage is not to be boosted.

3 more elements

A light-emitting element driving circuit comprising:

a brightness setting unit which sets a video image brightness based on a video image information signal from a video image processing circuit section, outputs video image brightness setting information, and outputs video image brightness change information;
a light-emitting element driving unit which drives a light-emitting element with a current of a current value corresponding to the video image brightness setting information from the brightness setting unit;
a detecting and comparing unit which detects a terminal voltage of a first terminal of the light-emitting element and compares with a predetermined voltage;
a voltage boost determining unit which determines whether or not a terminal voltage of a second terminal of the light-emitting element is to be boosted based on the video image brightness setting information and an output of the detecting and comparing unit;
and
a voltage boosting circuit section which boosts the terminal voltage of the second terminal of the light-emitting element when the voltage boost determining unit determines that the voltage is to be boosted and which does not boost the terminal voltage of the second terminal of the light-emitting element when the voltage boost determining unit determines that the voltage is not to be boosted.

3 more elements

Dependencies are inferred from the claim text.