10-A supercapacitor-based LED flash driver focuses ultra-slim camera phones and digital cameras

ON Semiconductor has introduced a new supercapacitor-optimized LED flash driver capable of delivering up to 10 A for photo flash and video light in ultra-slim camera phones and compact digital cameras.

When combined with the latest thin, prismatic supercapacitors – such as those offered by CAP-XX and licensed by Murata Manufacturing Co. Ltd., Japan with a capacitance of up to 0.9 F at 5.5 V – and the high-power LED OSLUX from Osram – ON Semiconductor's NCP5680 complements the Lithium-ion battery by supplying high-peak-current of up to 10 A for flash lighting optimized for use with the BriteFlash Power Architecture developed by CAP-XX. Fully programmable control of charging and discharging of the supercapacitor and overload protection ensures the right amount of light is provided for high-quality photography. The integrated driver can also power other high-peak-current circuits in portable systems, such as audio amplifiers, extending the useful battery operating time.

To produce high-resolution pictures in low-light conditions, cameras of 5 megapixels or more require a high-intensity flash. Today's WLEDs can deliver this level of light energy, but require up to 400 percent more power than a camera battery can provide. To support the battery, ON Semiconductor's NCP5680 manages a supercapacitor to drive the LED flash to full intensity, supplying high-peak-current up to 10 A. The integrated driver in the NCP5680 also manages the supercapacitor to handle other peak-power needs – zoom, auto-focus, audio, video, wireless transmissions, GPS readings and RF amplification – extending battery life without compromising slimline design.

The NCP5680 integrates all circuitry required to charge the supercapacitor, manage in-rush current and control LED current, thus saving designers development time, board space and component cost. Fully programmable control of charging and discharging of the supercapacitor ensures the right amount of light for high quality photography.

The I2C registers in the NCP5680 allow users to adjust the output current and flash duration of each of the two LEDs in real time. The solution can perform different lighting effects such as indicator light, pre-flash, and power flashlight for photographing and torchlight for video recording. When connecting to an ambient light sensor, the NCP5680 will automatically limit the flash duration to prevent photo over-exposure, thus preserving the photo quality. Additionally, the supercapacitor charging current is adjustable through an I2C register. NCP5680 can disable the charging operation during global system for mobile (GSM) transmission, in order to limit the current drawn from the battery.

Additionally, the NCP5680 has multiple built-in protection mechanisms, including flash time out, temperature detection, overload protection and short circuit protection. The device protects the flash circuitry from any faulty conditions of the driving circuit, as well as for the LED.

“The NCP5680, combined with an ultra-thin prismatic supercapacitor, delivers an ideal LED flash and power management solution for slim camera phones and digital cameras,” said Marie-Therese Capron, ON Semiconductor director of low voltage power management products. “This total LED flash solution supplies comparable light energy to xenon flash, but with only half of the comparable solution height and no need for an extra LED for video capture. Because the NCP5680 enables the Lithium-ion battery to support more power-hungry functions for a longer time, this new supercapacitor-based power management solution enables smart phones to offer ever richer functionality.”

Availability and Pricing

Available in the 3.5 mm x 3.5 mm x 0.55 mm uQFN-24 (micro-QFN-24) package, the NCP5680 is budgetary priced at $1.10 USD per unit in 3,000 unit quantities

Related links:

NCP5680 product details

NCP5680 datasheet

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