LASER DRIVING CIRCUIT FOR OPTICAL DISK RECORDING AND REPRODUCING DEVICE

摘要

PURPOSE:To prevent overshoot by controlling the current of a laser diode so that it is proportional to the digital storage value in a first or second storage means which is updated to set the current of the laser diode to a prescribed value at the time of preceding recording or reproducing. CONSTITUTION:8-beam data in a specific address of a RAM in a microcomputer 20 as first and second storage means is inputted to DA converters 25 and 26 and is converted to 256 kinds of voltage. Output terminals of DA converters 25 and 26 are connected to non-inverted input terminals of operational amplifiers 31 and 32, and output voltage of DA converters 25 and 26 are multiplied by (1+R10/R11) and (1+R12/R13) respectively and appear in output terminals of operational amplifiers 31 and 32. Thus, the rise or the fall is quickened to prevent the overshoot.