| 摘要 |
PURPOSE: A method for controlling a supply voltage of a laser diode and an electronic circuit are provided to gradually change a supply voltage to a direction of the second reference voltage when luminosity is measured, and to start controlling the supply voltage of a light source after reaching the second reference voltage, thereby being automatically adapted to a circuit configuration where a laser diode is disposed. CONSTITUTION: A comparator(102) of a control circuit(100) comprises input switches(S11,S12,S13,S14) for determining an output polarity of the comparator(102). The control circuit(100) comprises an active off circuitry(104) including switches(S31,S32) as well as two current sources(lu,ld). A safety block(106) is connected to the control circuit(100). The safety block(106) determines a time when a laser control is switched to a start-up step from an active off step, and generates an enable signal. A safety block(108) connected to the control circuit(100) determines whether a laser diode(112) is a PNP-type circuit configuration or an NPN-type circuit configuration.
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