Abstract: A laser diode monitoring system, including a thermistor, a monitoring unit, and a laser diode is disclosed. Thermistor is to receive a temperature for outputting an electrical temperature signal. The monitoring unit is coupled to the thermistor, and for receiving the electrical temperature signal to output a control signal. Laser diode, coupled to the monitoring unit, is for receiving the control signal to output a laser beam, wherein the temperature is determined based on the output power of the laser beam.

Abstract: A method is provided for determining whether a disk is positioned upside down inside an optical disk player. According to this method, a disk is loaded into an optical disk player, and then a laser beam is emitted that travels via a focusing device in the optical disk player to the loaded disk. Then, the focusing device is moved from a first position to a second position. While the focusing device is being moved from the first position to the second position, the variation in the intensity of the laser beam that is reflected by the disk is continuously recorded to produce a distribution curve of the intensity of the reflected laser beam. Thereafter, the method determines whether the disk is upside down based on the obtained distribution curve.

Abstract: A method of detecting a type of optical disc according to the rotation speed of a spindle motor loading the optical disc. First, the spindle motor is driven with a signal having a predetermined waveform. Next, the rotation speed of the spindle motor is detected by a Hall sensor and compared with a first predetermined rotation speed and a second predetermined rotation speed. When the detected rotation speed is faster than the first predetermined rotation speed, it is determined that there is no optical disc on the spindle motor, and it is determined that there is a mini-type optical disc on the spindle motor when the detected rotation speed is between the first predetermined rotation speed and the second predetermined rotation speed, and a normal-type optical disc is determined when the detected rotation speed is slower than the second predetermined rotation speed.