1.5A Boost Type Flash LED Driver
【產品特性】•Input Voltage Range : 2.8V to 5V
•Dual Channel Output
•Up to 1.5A Regulated Output Current (0.75A per Channel)
•Up to 85% Efficiency with Small Magnetics
•2MHz Switching Frequency
•Separate Flash Enable Input
•Separate Resistors Set Flash and Torch Mode Current
•User-Programmable Safety Timer
•Input Current Limit up to 2.5A
•Over-Voltage (Open LED, Open Circuit) and Over Temperature Protection
•Shutdown Current < 1μA
•RoHS Compliant and Halogen Free
•PDAs and Smart Phones
【文字介紹】The RT8515 is a high-efficiency, high-current boost converter capable of delivering up to 1.5A maximum output current. It is an ideal power solution for LED photoflash
applications in all single-cell Lithium-ion / polymer battery powered products.
The RT8515 maintains output current regulation by switching the internal high-side and low-side switch transistors. The transistor switches are pulse-width modulated at a fixed frequency of 2MHz. The high switching frequency allows the use of a small inductor and output capacitor, making the RT8515 ideally suited for small battery-powered applications. Pulse dimming is used to enable, disable and set the torch mode current level for the flash LEDs to one of 16 levels. The RT8515 also includes a separate Flash Enable input to initiate both flash / strobe operation and the default timer. The default timer can be used to terminate a flash event after a userprogrammed
delay or as a safety feature. A Flash Inhibit function is active when both Flash Enable and Flash Inhibit Enable go high. The maximum flash and torch mode current is set by external resistors respectively. One or two LEDs can be connected to the RT8515; when two LEDs are used, the output current is matched between each diode.
The RT8515 contains over-voltage protection, protection and a thermal management system to protect the device in the event of an open-circuit output. Built-in circuitry
prevents excessive inrush current during start-up. The shutdown feature reduces shutdown current to less than 1μA. The RT8515 is available in a tiny WQFN-16L 2x3 package to achieve best solution for PCB space and total BOM cost saving.