NS two can accurately control the brightness of the LED

June 9, 2006 - China News -- power management technology leader National Semiconductor Corporation Ns (National Semiconductor Corporation (America) listed on the New York stock exchange code: NSM) announced the launch of two new fixed frequency, electric current mode boost DC / DC converter. The two models were and LM3551 converter chip LM3552 using small 14 pin LLP package, and built two N n-channel field effect transistor (NFET), the portable electronic products for the built-in camera function to provide accurate brightness control function, to the brightness of the accurate control of flash light emitting diodes, the portable electronic products so these two converters are most suitable for built-in cameras such as mobile phones and personal digital assistant. The torch mode flash mode and low power LM3551 and LM3552 DC / DC converter with high power, the flashlight / flash pin drives one or more high current flash light emitting diode. The light emitting diode to avoid overheating, the user can choose the capacitor specific connection timeout value and flash pin, closing time set NFET internal transistor according to the capacitance, ensure the transistor after reaching the specified time will be automatically closed. LM3551 chip can use its external shutdown pin perform low power shutdown function, and LM3552 chip can be performed using the low power pin stop function. When the machine is stopped, the feedback resistance and the connection between the load and the input end can be switched off to avoid the leakage current to the ground. The soft start circuit the two chips have built-in user setting, so as not to start when a large number of surge current. In addition, the two chips is also provided with an overvoltage protection circuit, and switching frequency up to 1.25MHz, so the system design engineers can use smaller volume and lower cost and lower the rated voltage of the output capacitor. The main features of LM3551 and LM3552 two chips: drive current total of 1A flash flashlight / overtime protection independent flash / shutdown mode in stop mode, soft start function of light emitting diode was completely shut off can be set for constant switching frequency wide input voltage range surge the current limit over-voltage protection 2.7V to 5.5V the 1.25MHz with compact and slim non pull 14 pin LLP package, only 4mm x size 4mm for further information about LM3551 and LM3552 two chip data or order related samples. Can browse the http://www.national.com/pf/LM/LM3551.html and http://www.national.com/pf/LM/LM3552.html "etc.. According to national semiconductor power management products according to iSuppli in semiconductor market 2005 years for the share survey, national semiconductor is the world's largest regulator chip suppliers, market share up to 14%. National Semiconductor with innovative power management products every kind of, including linear regulator, power monitoring, control and voltage reference IC leading the industry, as well as a variety of switching converter, such as high voltage DC / DC converter integrated circuit, switched capacitor converter, light management integrated circuit and inductive switching converters. The American national semiconductor is particularly designed to provide a wide range of online design engineers with a variety of online design tools, allowing engineers to design their system to select the best power management chip. System design engineers can also WEBENCH design "login national semiconductor products on the Internet, and then design and analysis system design, then using tailor-made packages for modeling, suite more will ensure to customers in the shortest time. For further information about national semiconductor power management products, can browse the http://power.national.com/CHS page. Price and availability of LM3551 and LM3552 two chips have been a large number of stock, also in 1000 a procurement unit, single price of 1.10 dollars for the same. In addition, these two chips are also available without lead packaging options. National Semiconductor Corporation Ns national semiconductor is a leading provider of simulation technology providers, analog chips and subsystems has been committed to the development of high value-added. The company's advanced products include power management circuits, display drivers, audio and operational amplifiers, communications interface products and data conversion solutions. National Semiconductor's analog chip products are mainly for mobile phones, display and wide electronic products market, including the market of medical equipment, automotive electronic system, industrial system and test and measurement equipment and other products. National Semiconductor Corporation in the United States of California (Santa Santa Clara Clara), as of 2005 fiscal year ending May 29, 2005 turnover of $1 billion 910 million. About the national semiconductor company information and product introduction, welcome to visit the company's Web site, web site: www.national.com/CHS.