A method of controlling laser source power of a semiconductor laser and the apparatus a recording and reproducing method and apparatus of optical-magnetic recording medium and a recording and reproducing method and apparatus of optical recording medium

摘要

A laser power supply control method of a semiconductor laser for applying a power supply voltage to a collector and an emitter of an output transistor and to a series circuit of a semiconductor laser so as to control a laser power source of a semiconductor laser, Can be reduced. A variable power supply voltage (Vcc) is applied to a series circuit of an output transistor (Qb) and a semiconductor laser (SL), and the variable power supply voltage (vcc) and the peak-The variable power supply voltage Vcc is controlled so that the difference between the power supply voltage Vcc and the power supply voltage Vcc becomes substantially constant.