| 摘要 |
An optical pickup with a laser driver circuit is provided to overcome an increase in size of an optical pickup, which is caused by a ferrite bead or capacitor being provided in a drive current path to reduce EMI noise effects. In an optical disc apparatus, an optical sensor element detects a laser beam from a laser emission element included in an optical pickup circuit and then sends the detected signal to a main circuit board. An APC circuit in the main circuit board outputs a control signal to control the laser output from the laser emission element at a constant level in accordance with the detected signal from the optical sensor element. A laser driver circuit included in the optical pickup circuit incorporates a transistor and a high-frequency wave superposition circuit). The transistor produces a drive current in accordance with the control signal from the APC circuit, while the high-frequency wave superposition circuit superposes a high-frequency current on the drive current. The drive current superposed with the high-frequency current drives the laser emission element.
|
