DEVICE FOR CONTROLLING LASER POWER

摘要

PURPOSE: A device for controlling laser power is provided to strictly control a peak power as well as an erase power under the presence of noise. CONSTITUTION: A monitor circuit(2) monitors/converts the output of a photo diode(1) into voltage. A peak hold circuit(20) holds a peak of the voltage output from the monitor circuit when a pit is recorded and outputs the voltage without hold when the pit is erased. An output selector(44) selects one of the output from the monitor circuit and the output passing the peak hold circuit, and outputs the selected output. The first sample hold circuit(45) obtains the first voltage by the sample hold from the output of the output selector. The second sample hold circuit(46) obtains the second voltage by the sample hold from the output of the output selector. Analog/digital converting circuits(47,48) convert the output of the first and the second sample hold circuit into a digital signal. Digital/analog converting circuits(50,51,52) convert the output of an operation circuit(49) into an analog signal. Switches(32,33,34) turn on/off between the power sources(29,30,31) and the laser diode(15).