Patent ID: 7554895

Claim:
An apparatus for controlling a data write operation in an optical storage system comprising: an operational amplifier having a positive input end, a negative input end and an output end for outputting a write-control signal at the output end, the operational amplifier being operated in one of a short-term mode, a long-term mode and a closed-loop mode; a first gain amplifier for amplifying a first input signal on its input end; a second gain amplifier for amplifying a second input signal on its input end; a first switch having a first end connected to an output end of the first gain amplifier; a second switch connected to the output end of the operational amplifier and the negative input end of the operational amplifier; a third switch having a first end coupled to the first switch and a second end connected to the negative input end of the operational amplifier; a fourth switch for coupling the output signal of the second gain amplifier to the positive input end of the operational amplifier; a fifth switch having a first end connected to the first switch and a second end connected to the fourth switch; a sixth switch for coupling a DAC signal or a ground signal to the fourth switch and fifth switch; and a seventh switch for coupling the DAC signal or the output of the operational amplifier to an input end of the second amplifier; wherein: in the short-term mode, the operational amplifier is formed as a voltage follower for initializing the write-control signal; in the long-term mode, the operational amplifier charges the write-control signal, the output end of the operational amplifier is coupled to the negative input end of the operation amplifier and the positive input end of the operational amplifier is coupled to a voltage level used for recording data onto storage medium for charging the write-control signal such that the positive input end and the negative input end of the operational amplifier are virtually grounded; and in the closed-loop mode, the charged write-control signal is employed to record data on the storage medium.