封装：DFN2030-14L

General Description

    The AS6585B is a 3MHz fixed frequency synchronous boost converter, optimized for 0.75A/ch, total 1.5A flash current output LED driver with PWM dimming function, for distance dimming camera flash LED application and maximum 800mA movie mode applications using high-current white LEDs in all single cell Li-ion powered products. An adaptive regulation method ensures the current for each LED remains in regulation and maximizes efficiency.

    Two simple logic control inputs (ENM and ENF) enable and disable flash and movie mode operation of the AS6585B. The movie-mode and flash-mode current levels are independently fixed by two separate resistors (RSETM and RSETF).

    For flash mode, a default timer 800mS can be used either to terminate a flash event or as a safety flash timer. One or two LEDs can be connected to the AS6585B; in the case of two LEDs the output current is matched between each diode. The real LED current at flash mode and movie/torch mode can be programmed by external PWM signal at ENM pin.

    The AS6585B integrate an intelligent flash current control mode: during flash current turn-on the input voltage falls below the flash mode VIN Monitor threshold, the flash current is stopped at the level that the current ramp had risen to, at the time of the VIN Flash Monitor events.

    The AS6585B contain a thermal management system to protect the device; a internal over-voltage protection (OVP) circuitry prevents damaged to the AS6585B from open LED or open circuit conditions; and a cycle-by-cycle current limit prevents damage to the AS6585B. Built-in circuitry prevents excessive inrush current during start-up. The shutdown feature reduces quiescent current to less than 1.0μA.

    The 3MHz switching frequency allow for the use of tiny, low profile (0.47uH or 1.0uH) inductors and 4.7uF ceramic capacitors. The device is available in 14-pin 2mmX3mm DFN package and is rated over the -40°C to 85°C.