| 摘要 |
In a power controlling device for laser emitting apparatus, a laser diode and a photodiode are provided. Current is generated by the photodiode in accordance with the intensity of laser beam received. The current flows across a resistor to generate a voltage, which is compared with a reference voltage. There is further provided a circuit for generating the reference voltage, which includes a pulse signal generating circuit in which a duty cycle of the pulse signal is changeable, and a voltage generator which generates voltage in accordance with the duty cycle of the pulse signal. The laser diode is driven in accordance with the result of comparison of the voltage generated by the resistor with the reference voltage which is adjusted in accordance with the duty cycle of the pulse signal.
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