| 摘要 |
PURPOSE:To obtain the driving current of a semiconductor laser to a maximum in limited current and voltage by providing two driving circuits and making the current, to which the output current from each of the driving circuits is added, the driving current of the semiconductor laser. CONSTITUTION:At the time of a recording, a SW1 and a SW2 are connected with the side of a contact (a) and the side of a contact (c), respectively. A driver 7 and a driver 8 perform the automatic power control (APC) of the driving current of a semiconductor laser 9 corresponding to recording power and reproducing power, respectively, the output of the drivers 7, 8 is added and it is driven to the laser 9. At the time of an erasure, the SW1 and the SW2 are connected with the side of a contact (b) and the side of the contact (c), respectively, and bias voltage Vb corresponding to the driving current which is abount the half of erasure power is imparted to the driver 7. Then, the driver 7 does not perform the APC and the laser 9 is driven by the current that the output current of the drivers 8 and 7 is added. Thus, the driving current of the laser 9 is obtained to a maximum. |
