1.5A Flash LED Driver with I²C Compatible Interface

The RT8540 is a high efficiency synchronous Boost converter capable of delivering up to 1.5A maximum output current. It is an ideal power solution for up to three LEDs photoflash applications in all single-cell Lithium-ion/polymer battery powered products. The RT8540 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 RT8540 ideally suited for small battery powered applications. The RT8540 also includes STRB0, STRB1, Tx-MASK input to simplify torch and flash synchronization with the camera module. The default timer can be used to terminate a flash event after a user programmed delay or as a safety feature. The device automatically optimizes the LED flash current budget with the battery voltage condition as a feature.

The RT8540 not only operates as a regulated current source, but also as a voltage Boost regulator with the capability of down output voltage mode. The RT8540 contains over-voltage protection, over-current protection and a thermal management system to protect the device. The shutdown feature reduces shutdown current to less than 1μA. The RT8540 is available in the tiny WL-CSP-20B 1.82x2.22 (BSC) package to achieve best solution for PCB space and total BOM cost saving.