Patent ID: 7830436

Claim:
A method for controlling a semiconductor device including a signal obtaining unit and column processors, the signal obtaining unit including unit elements arranged in rows and columns, the unit elements each including a charge generator for generating signal charges corresponding to incident electromagnetic waves and a signal generator for generating a signal corresponding to the signal charges generated by the charge generator, the column processors being provided for the respective columns to read the signals on a row-by-row basis, to amplify the signals by predetermined gains, and to sequentially output amplified signals, the column processors respectively including amplifier circuits for amplifying the signals read from the unit elements by gains set to the amplifier circuits, the method comprising: a gain-determination controlling step of detecting signal levels of output signals of the amplifier circuits or of subsequent stages thereof with different gains set to the respective amplifier circuits, determining gains to be set to the amplifier circuits based on a classification of each of the detected signal levels in which the classification indicates that a high signal level is to be amplified using a smaller gain than a low signal level, and causing the amplifier circuits to operate with the gains determined, wherein, when signal levels of output signals from the amplifier circuits with predetermined gains set to the amplifier circuits fall outside linear ranges of the amplifier circuits, a maximum gain allowed to be set for each of the amplifier circuits except for the predetermined gain is set to the amplifier circuits.