| 摘要 |
PURPOSE:To reduce the area of a comparator in a chip by using one comparator so as to discriminate to which of plural stages of levels the brightness belongs. CONSTITUTION:An electric charge is generated when a light is radiated to a photoelectric conversion section and the electric charge is stored in a storage section. On the other hand, the luminous quantity radiated to the photoelectric conversion section is monitored by a brightness monitor means, the generated electric charge is stored in a storage means, a signal in response to the quantity of the stored charge is outputted from an output means and inputted to one input of the comparator 45. On the other hand, a reference voltage generating circuit RVC generates plural stages of reference voltages and they are inputted to the other input of the comparator 45. Thus, the comparator 45 compares the plural reference voltages with the output from the output means 10-2 to decide to which or plural stages the brightness corresponds. Thus, the area of the comparator in the chip is reduced considerably. |
