The United States announced the launch of a high current flash LED driver

National Semiconductor announced the launch of a high current flash LED driver for portable multimedia devices in the camera flash drive two LED. This model LM3553 driver belonging to the national semiconductor PowerWise an energy-efficient chip series, can drive one or two tandem LED, such as mobile phone, PDA, smart phones, portable scanner and medical strobe lights and other portable electronic products.

LM3553 LED flash drive national semiconductor is a fixed frequency boost DC / DC converter, built-in two stable current receiver, only a lithium battery can output load current up to 1.2A. Using adjustable overvoltage protection function, this chip can drive two serial high current LED to further improve the brightness / power ratio of the device.

The LM3553 chip is not only equipped with a high power flash mode to ensure that the camera has enough light to take a picture, but also has a low power flashlight mode, so that there is enough light to shoot a video clip. In addition, this chip also has 128 flash current level and 16 flash timing. System design engineers as long as the I2C compatible interface can be set for individual applications corresponding to the current level and timing. The LM3553 chip also features a timeout protection circuit to prevent flash LED from being damaged during fault operation.

LM3553 LED flash drive can be low power system output light intensity increased to more than 90%, so it is included in the national semiconductor PowerWise chip series high efficiency theory. The switching current limiting value of the LM3553 chip can be flexibly adjusted according to the requirement, which is convenient for the system to adopt a small inductor with low saturation current. This chip can be used to provide 5V power supply voltage mode LED backlight and audio amplifier.

Through the internal registers or the FEN and TX pins, the chip is set to a high power flash mode or a low power flashlight mode, thereby driving one or more high current LED. The TX input can be forced to change the flash mode to the low current flashlight mode, so that the flash pulse can be synchronized with the RF power amplifier application or other high current operation mode. Built in general purpose input / output pins provide hardware support for the system. If the system fails, the hardware reset pin will be fully controlled by the chip. In addition, the chip's internal soft start function can avoid the start and fast switching frequency when there is a lot of inrush current, which allows the design of a smaller external components.