A photoelectric speed measuring chip

Abstract

The invention discloses a photoelectric speed measuring chip. The chip comprises a first photosensitive detection module, a second photosensitive detection module, a third photosensitive detection module and a fourth photosensitive detection module, wherein the four photosensitive detection modules are identical in shape and size, the chip further comprises a first comparator, a second comparator,a sequential control module and a voltage controlled oscillator, an output end of the voltage controlled oscillator is connected with the sequential control module, output ends of the first photosensitive detection module and the third photosensitive detection module are connected with positive and negative input ends of the first comparator, output ends of the second photosensitive detection module and the fourth photosensitive detection module are connected with positive and negative input ends of the second comparator, and output ends of the first comparator and the second comparator respectively output a first output signal and a second output signal. The chip is advantaged in that the chip is simple in structure and has relatively small land occupation area, and the rotation speed ofa code disc can be determined accurately according to the output of the comparators.

Description

technical field [0001] The invention relates to the field of photoelectric speed measurement, in particular to a photoelectric speed measurement chip. Background technique [0002] The photoelectric speed measuring chip is used to detect the changing frequency of the light irradiated on the chip, and then obtain the rotational speed of the code disc or the moving speed of the code bar that blocks the incident light. It is widely used in electromechanical products to realize the detection of workpiece speed. For example, detecting the rotation speed of the motor, detecting the rotation speed of the sensing parts, and so on. [0003] At present, most of the photoelectric speed measuring chip products use BJT technology, and use two photosensitive diodes to detect the light and dark changes of the incident light passing through the code disc. The photocurrent generated by the corresponding photodiode changes, and then outputs high and low pulse signals, and then calculates th...

AI Technical Summary

Problems solved by technology

However, in the CMOS process, the offset and process change are large, and this circuit architecture cannot be used in the CMOS process

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