Abstract: An apparatus and method is provided for use on the pickup head of an optical disc drive for the purpose of adjusting the pickup head to the optimal focus point through a featured tree-structured search algorithm. The apparatus and method can perform the adjustment automatically so as to eliminate the need to use laborious work to make the adjustment in manufacture. The apparatus is activated each time the optical disc drive is started so as to offset the unbalanced condition in the focusing error signal, which allows the optical disc drive to perform the access operation more reliably. Moreover, the apparatus is realized in a digital manner that allows easy implementation and a low manufacturing cost.

Abstract: A CD-ROM control chip is provided for a use of firmware information update in the CD-ROM system. The control chip at least includes a microprocessor, a decoder, a controller, and an extra memory. The microprocessor is coupled to a data bus, and further coupled to an external ROM, which stores all firmware information. The decoder is coupled to the microprocessor through the data bus, and is also coupled to an external buffer memory and an external main board interface. The external main board interface allows the CD-ROM control chip to communicate with an external computer. The controller is coupled to the decoder, and is coupled to the microprocessor the data bus. The controller is used to receive information and control signals from an external CD. The extra memory is coupled to the microprocessor through the data bus.

Abstract: An auto gain adjustment apparatus and method are provided for the focusing/tracking control of the optical pickup of an optical disc drive. The gain is obtained by utilizing the self-sustained oscillation from a non-linear component in the optical disc drive, such as a relay circuit with hysteresis. This gain adjustment apparatus and method is more advantageous than the prior art in that the gain can be automatically adjusted without involving manual work and the need to apply an externally generated oscillating test signal. The apparatus and method therefore allows the manufacture and utilization of the optical disc drive to be more efficient and cost-effective.