| 摘要 |
PURPOSE:To obtain an output stable against variations in temperature and in voltage by providing parts, composed of the same circuit in terms of direct current, to an amplifier which amplifies the output of a photo-detecting element and a reference voltage circuit which outputs a reference voltage. CONSTITUTION:The output of a photodetecting element 20 is amplified by an amplifier 21, whose output is compared with the reference voltage of a reference voltage circuit 22 by a comparator 24. This reference voltage circuit 22 has the same circuit constitution with the amplifier 21, and is integrated on the same semiconductor element with the amplifier 21. The output of this reference voltage circuit 22 is given a slight offset voltage by a level shifting circuit 23, and the resulting output is applied to a comparator 24. Consequently, an invariably normal output signal varying with temperature and a voltag appears at the output of the amplifier 21 and reference voltage circuit 22. |
