1-2. ALPC (Automatic Laser Power Control) Circuit

ALPC function DVD/CD anlaog front-end IC(IC101 R2S35002) is for constant power control purpose. Based on the accurate power sensor(FMON) in P/U, ALPC feedback loop maintains constant power level against laser diode’s temperature variation.

The ALPC loop amplifies(10x) the FMON signal to enhance the accuracy of read power level control. Swithching of amplification is made by combination of a logical WGATE signal and a logical RWAPC signal.

There are two set of APCDAC, which are used at different term to monitor different power level. Generally, the one is used at reading and the other one is used at writing. The logical WGATE signal which is switched between reading and writing changes the two APCDAC.

The ALPC loop supplies same currency (IAPC) to Laser Diode Driver(LDD) during reading and writing.

There is another ALPC which controls Full-Scale-DAC (FsDAC). FsDAC determines scale of WDAC of Laser Diode Driver. MPU monitors write-power level of FMON signal and changes FsDAC directly to maintain constant write-power level. There are two write power signal. The one is based on S/H signal and the other one is based on B/H(Bottom-Hold) signal. The write power levels are monitored as digital levlels which are converted by built-in Anlog-Digital Converter in DSP. The MPU monitors each write power level and calculates proper setting of FsDAC, and changes value through serial interface between LDD and DSP.

48

Page 43 Page 45
Page 44
Image 44
LG Electronics GSA-4167B, GSA-4168B, GSA-4165B service manual Alpc Automatic Laser Power Control Circuit
Page 43 Page 45

GSA-4167B, GSA-4165B, GSA-4168B specifications

LG Electronics has been a prominent name in the electronics industry, particularly known for its innovative optical storage solutions. Among its noteworthy products are the GSA-4167B, GSA-4165B, and GSA-4168B DVD writers, each showcasing a blend of advanced technology and user-friendly features tailored to meet diverse consumer needs.

The LG GSA-4167B stands out for its versatility and performance. This model supports a wide range of disc formats, including DVD-R, DVD+R, DVD-RW, DVD+RW, and dual-layer DVDs, enhancing its usability for various applications. With a generous writing speed of up to 16x for DVD+R and 8x for dual-layer DVDs, users can create and backup data efficiently. This device is equipped with LG’s Super Multi technology which allows it to read and write multiple formats, making it a perfect choice for users who wish to maximize their media experience without being restricted to a single format.

The GSA-4165B, though slightly older, remains popular due to its reliable performance and ease of use. This model also supports a wide array of formats and achieves impressive speeds comparable to its counterparts. With features such as Buffer Under Run Technology, the GSA-4165B minimizes interruptions during the burning process, reducing the risk of damaging data. Additionally, its sleek design makes it appealing for desktop setups, offering both aesthetics and practicality.

On the other hand, the LG GSA-4168B is known for its advanced capabilities, particularly in terms of burning dual-layer DVDs. Supporting speeds up to 16x for standard DVDs and 4x for dual-layer formats, it combines speed with efficiency. This model incorporates LightScribe technology, enabling users to etch labels directly onto specially coated discs, adding a personal touch to data storage. Its efficient cooling system helps maintain performance during extensive usage, ensuring longevity and reliability.

All three models represent LG's commitment to quality and innovation in optical storage technology. With features such as Power Burn technology and Seamless Link, they provide users peace of mind during high-speed data transfers. Their compatibility with different operating systems further enhances their versatility, making them suitable for both home users and professionals. Overall, the GSA-4167B, GSA-4165B, and GSA-4168B are exemplary models that reflect LG Electronics' dedication to advancing technology and enhancing user experience in the realm of optical drives.
Top Page Image Contents