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(11) | EP 2 675 246 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Semiconductor-light-source control device |
| (57) A semiconductor-light-source control device includes a regulator and a driving control
section. The regulator generates a driving current flowing through a semiconductor
light source. The driving control section controls the regulator so that a magnitude
of the driving current approaches a target value. A luminance of the semiconductor
light source is adjusted by repeating a first state in which the magnitude of the
driving current is controlled to approach the target value and a second state in which
the driving current is smaller than that in the first state. Both the duty ratio of
the first and second states and the target value change according to a setting value
of the luminance of the semiconductor light source. One of the target value and the
duty ratio is set so as to have a one-to-one correspondence relationship with the
setting value.
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