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  Seaward Introduces Series LED Driver for Digital Camera and Cellphone Applicatio... Publication:2006-5-21 

Media Contact:
Monica Dong
Seaward Electronics INC.
010-8289-5700x 8020
monica@seawardinc.com.cn

Seaward Introduces Series LED Driver for Digital Camera and Cellphone Applications

May 21, 2006 - Seaward today introduced the SE3506, a high efficiency white LED driver for the backlighting in Cellphones, Digital Cameras, Portable DVDs, MPEG4 and other similar applications. The SE3506 is a step-up DC/DC converter specifically designed to drive white LEDs with a constant current.  The device can drive two, three, four, five, or six LED’s in series from a single Li-Ion cell.  Series connection of the LEDs provides identical LED current resulting in uniform brightness and eliminating the need for ballast resistors.  The SE3506 switches at 1MHz, allowing the use of any tiny external components.  The output capacitor can be as small as 1μF, saving space and cost versus alternative solutions.  A low 95mV feedback voltage minimizes power loss in the current setting resistor for better efficiency. The EN Pin is available to be used to disable or enable the SE3506 or turn on and off the LED’s. Furthermore, this EN Pin can be used to control the brightness of the LED’s, without the need of changing any components on the PCB. A frequency of different duty-cycle can be sent to the EN Pin to control the amount of time the LED’s will stay on. The longer the time the LED’s are turned on, the brighter the LED’s. The longer the time the LED’s are turned off, the dimmer the LED’s. SE3506 can take Vin from as low as 2.0v and as high as 5.0v. This covers the entire lifespan of all types of Lithium batteries, which typically is charged up to 4.2v when newly charged and drops to about 2.7v before it switches off.

SE3506 has a typical supply current of only 100uA. This is about 10x to 20x smaller than the typical LED drivers of the similar type. This provides the maximum power savings in portable applications, which are typically power by batteries and the low power consumption is very important.

SE3506 has built-in over-temperature protection (OTP). When the temperature reaches about 150C, the IC will enter shutdown mode to provide proper protection. This will make sure both SE3506 and the appliance that uses SE3506 will not be damaged. In addition, SE3506 has built-in over-current protection (OCP). In case the load is accidentally short-circuited, or too heavily loaded. In some cases, such as the load is accidentally shorted circuited, the OCP and OTP will work in conjunction to provide the best protection for the IC and for the appliance.

SE9016 can be used in conjunction with SE3506 (White LED driver) and SE5221 (Dual-Channel LDO) for cellphone applications. They provide a common chipset solution to portable applications where Lithium battery and LCD panel are both present.

 

SE3506 is available in low profile SOT-23-5L package.

Key Features for SE3506:

·         VIN range: 2.0V-5.0V

·         Inherently Matched LED Current.

·         High Efficiency: 85% Typical.

·         Drives Up to Four LEDs from a 3.0V Supply.

·         Drives Up to Six LEDs from a 3.6V Supply.

·         Fast 1MHz Switching Frequency.

·         Up to 35V max output voltage.

·         Uses Tiny 1mm Tall Inductors.

·         Requires Only 1μF Output Capacitor.

·         Low Profile SOT-23-5L Packaging.

·         Supply Current is 100uA typical

·         Output over-current protection

·         Thermal protection

·         ESD protection better than 2KV

·         SOT23-5L

 

Packaging, Pricing and Availability
Seaward’s SE3506 is available now in a 5-lead SOT23. 

About Seaward Electronics INC
Seaward Electronics INC, a young and energetic startup specialized in Analog and mixed signal IC’s, designs Power Management devices for a variety of applications. Seaward’s leading-edge products are used in wireless handsets and LANs, Digital cameras, cellphones, chargers, PCs and laptops, MPEG4s, MP3s, portable DVDs, and Flash storage devices. Seaward designs its products at both Silicon Valley in the United States and Beijing in China. Seaward has sales’ offices at Taipei(Taiwan), Beijing(China), Shen Zhen(China), Shanghai(China), and Milpitas (USA).