Laser diode light emission sensing circuit

A laser diode light emission sensing circuit for sensing a luminous state of the laser diode, comprises:

• a light sensor for sensing a lightwave signal of said laser diode to convert it into a current signal,
• a current/voltage converting device for converting a current signal from said light sensor into a voltage signal,
• a comparator for comparing a voltage signal from said current/voltage converting device with a reference voltage from a reference voltage producer to output a predetermined signal when the voltage signal from said current/voltage converting device exceeds said reference voltage from said reference voltage from said reference voltage producer,
• said reference voltage producer for outputting said reference voltage to said comparator,
• a first output inverter for inverting an output of a CELL signal rising before starting a light emission term wherein said laser diode repeats continually light emission and light outing, and falling from termination of said light emission term, and
• a delay flip-flop which utilizes an output of said comparator as a clock input, and which utilizes an output of said first output inverter as a reset input, and maintains a data input at a high level.

A laser diode light emission sensing circuit for sensing a luminous state of the laser diode, comprising:

• a light sensor for sensing a lightwave signal of said laser diode to convert it into a current signal,
• a current/voltage converting device for converting a current signal from said light sensor into a voltage signal,
• a comparator, for comparing a voltage signal from said current/voltage converting device with a reference voltage from a reference voltage producer to output a predetermined signal when the voltage signal from said current/voltage converting device exceeds the reference voltage from said reference voltage producer,
• said reference voltage producer for outputting said reference voltage to said comparator, and
• a delay flip-flop which utilizes a CELL signal falling before starting a light emission term, wherein said laser diode repeats continually light emission and light outing, and rising from termination of said light emission term, as a reset input, and which utilizes an output of said comparator as a clock input, and maintains a data input at a high level.

A laser diode light emission sensing circuit for sensing a luminous state of the laser diode, comprising:

• a light sensor for sensing a lightwave signal of said laser diode to convert into a current signal,
• a current/voltage converting device for converting a current signal from said light sensor into a voltage signal,
• a comparator for comparing a voltage signal from said current/voltage converting device with a reference voltage from reference voltage producer to output a predetermined signal when the voltage signal from said current/voltage converting device exceeds the reference voltage from said reference voltage producer,
• said reference voltage producer for outputting said reference voltage to said comparator,
• a second output inverter for inverting an output of a CELL signal rising before starting a light emission term wherein said laser diode repeats continually light emission and light outing, and falling from termination of said light emission term,
• a third output inverter for inverting an output of said predetermined signal from said comparator,
• an NOR circuit utilizing a signal from said second output inventer and a signal from said third output inverter as inputs to output a predetermined signal when both the signals are at a low level, and
• a set-reset flip-flop utilizing an output of said NOR circuit as a set input and utilizing a signal from said second output inverter as a reset input.

A laser diode light emission sensing circuit for sensing a luminous state of the laser diode, comprising:

• a light sensor for sensing a lightwave signal of said laser diode to convert it into a current signal,
• a current/voltage converting device for converting a current signal from said light sensor into a voltage signal,
• a comparator for comparing a voltage signal from said current/voltage converting device with a reference voltage from a reference voltage producer to output a predetermined signal when the voltage signal from said current/voltage converting device exceeds the reference voltage from said reference voltage producer,
• said reference voltage producer for outputting said reference voltage to said comparator,
• a third output inverter for inverting an output of the predetermined signal from said comparator,
• an NOR circuit utilizing a CELL signal falling before starting a light emission term wherein said laser diode repeats continually light emission and light outing and rising from termination of said light emission term as well as a signal from said third output inverter as inputs to output a predetermined signal when both the signals are at a low level, and
• a set reset flip-flop utilizing an output of said NOR circuit as a set input and utilizing said CELL signal as a reset input.