SEMICONDUCTOR DEVICE, AND ELECTRONIC APPARATUS USING THE SAME

摘要

PROBLEM TO BE SOLVED: To adjust how easily a luminance of a light source is varied in accordance with a use state when adjusting the luminance of the light source of a display screen etc., in accordance with an ambient luminance.SOLUTION: A semiconductor device 3 includes: a power source unit 7 for an illuminance sensor which is configured to supply electric power to the illuminance sensor 1; a current/voltage conversion unit 9 configured to convert a detection current from the illuminance sensor 1 into a voltage signal; a storage unit 11 storing a plurality of voltage signal thresholds corresponding to ambient illuminance levels; an ambient illuminance level determination unit 13 configured to intermittently determine an ambient illuminance level by comparing the voltage signal from the conversion unit 9 with the voltage signal thresholds in the storage unit 11 and to output an ambient illuminance level signal corresponding to the ambient illuminance level; an identical-ambient-illuminance-level frequency determination unit 15 configured to output an automatic dimming start signal corresponding to the ambient illuminance level signal when the determination unit 13 outputs identical ambient illuminance level signals successively only by a predetermined frequency; and a power source unit for a light source 19 configured to make the external light source 5 light with a luminance corresponding to the automatic dimming start signal.