Application of super capacitor to illuminate the application of high-power LED in the camera phone

The combination of high power LED and super capacitor will be able to solve the key problems in the application of high quality LED flash in the camera mobile phone.

Although some of the current camera phones have high-quality lenses, image processing software, high pixel image sensor, but in order to take a perfect picture, there is still a large area to be developed. There are few camera phones that can be imaged in a hotel, bar, or room with a low brightness.

The key factor to solve this problem is to use a flash to provide adequate illumination during the photo shoot. A method for measuring the light intensity, light illumination Statistics (unit: Lux) in flash time accumulation and. A light intensity in 10-15 seconds. Lux can be enough light shooting images with high resolution.

Many camera phones have been using the LED flash, but because of lack of light, so the purpose is not fully achieved. The majority of mobile phone equipped with 1-2 watt LED, only one meter distance to provide less than 4 lux. Second light intensity, distance to 2 meters, only less than 1 lux seconds.

Rapid development of high-power LED. However, in order to achieve maximum brightness, and now the mobile phone battery can provide 800-1000mA, they need more than 400% drive current.

Xenon flash lamp

As another alternative to the LED, some of the latest camera phones are powered by xenon flash lamps, which are designed specifically for flash

Custom door, using capacitive drive. Xenon flash provides excellent brightness for a short exposure time, ideal for shooting moving objects and lighting up distant targets.

Xenon flash, however, requires a large capacity capacitor, which is huge. For example, in Sony Ericsson's K800 phone, xenon flash and peripheral circuits occupy 3.8 cubic centimeters. At the same time, in close proximity to the ear, the storage of up to 330V, 1.5 joules of energy, there are certain security issues. Not only that, it takes a long time (8 seconds) for Sony Ericsson to recharge between the two shots.

Xenon flash, however, is not the only option. Australia's CAP-XX research and development technology allows the use of high power LED camera phone can have a different appearance. The company is dedicated to the user to create the shape of the narrow super capacitor, they saw the opportunity to combine this capacitor and high-power LED. In the construction of the BriteFlash LED CAP-XX flash, the super capacitor is used to provide the current drive LED (1A or more), the phone battery is only used to charge the capacitor between the flash can be.

According to deputy general manager of CAP-XX Pierre Mars, if the voltage of a 0.5F capacitor 1V release in the flash process, so it only needs 250mA the current time for charging 2 seconds can be used to shoot a photo. This feature is smaller than the current standard LED flash required current specifications.

Source: Electronic Design Technology