| 摘要 |
Optical disc drives designed for reduced power consumption switch the supply voltage in three stages between first, second, and third power supplies, but the reduction in power consumption that is possible in the drive circuits with three stage switching control is limited. A drive output tracking signal is generated according to the waveform of the drive output that drives the focus and tracking actuators, and this drive output tracking signal is applied to a step-up type focusing and tracking power supply. The step-up power supply controls the fixed output according to the drive output tracking signal, and when the drive output is greater than the fixed output, control output that is greater than or equal to the fixed output and slightly greater than the drive output is generated. This control output is supplied to the focus and tracking drive circuits to produce drive output.
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