| 摘要 |
PROBLEM TO BE SOLVED: To provide a distance measuring circuit to use a CMOS structure capable of eliminating the need for NPN transistors to be externally arranged and reducing the number of component parts. SOLUTION: A distance measuring circuit to use a CMOS structure is constituted of a light projecting part 1 to project a pencil of light toward an object 2 of distance measurement, a semiconductor location detector 4 to receive the reflected light of the pencil of light from the object 2 of distance measurement and to output a pair of signal currents according to the distance to the object 2 of distance measurement, current-voltage converting parts 15A and 15B to convert the pair of signal currents into a pair of signal voltages, voltage-current converting parts 16A and 16B to reconvert the pair of signal voltages outputted from the current-voltage converting parts into a pair of amplification currents, a logarithmic compressing means to input the pair of amplification currents outputted from the voltage-current converting parts each to the emitters of parasitic PNP transistors 8A and 8B formed in a CMOS structure and to output a pair of logarithmic compression signals, and a computing part 10 to obtain the distance to the object 2 of distance measurement from the pair of logarithmic compression signals.
|
