General
Description
Two simple logic control inputs (ENM and ENF)enable and disable flash and movie mode operation ofthe AS6585B. The movie-mode and flash-modecurrent levels are independently fixed by two separateresistors (RSETM and RSETF).
For flash mode, a default timer 800mS can beused either to terminate a flash event or as a safetyflash timer. One or two LEDs can be connected to theAS6585B; in the case of two LEDs the output current ismatched between each diode. The real LED current atflash mode and movie/torch mode can be programmedby external PWM signal at ENM pin.
The AS6585B integrate an intelligent flash currentcontrol mode: during flash current turn-on the inputvoltage falls below the flash mode VIN Monitorthreshold, the flash current is stopped at the level thatthe current ramp had risen to, at the time of the VINFlash Monitor events.
The AS6585B contain a thermal managementsystem to protect the device; a internal over-voltageprotection (OVP) circuitry prevents damaged to theAS6585B from open LED or open circuit conditions;and a cycle-by-cycle current limit prevents damage tothe AS6585B. Built-in circuitry prevents excessiveinrush current during start-up. The shutdown featurereduces quiescent current to less than 1.0μA.
The 3MHz switching frequency allow for the use oftiny, low profile (0.47uH or 1.0uH) inductors and 4.7uFceramic capacitors. The device is available in 14-pin2mmX3mm DFN package and is rated over the -40°Cto 85°C.
Features
Input Voltage Range : 2.7V to 5.0V
Power On Flash Mode Spurious TriggeringSuppress
Up to 3.0MHz Switching Frequency forSmaller Inductor Using
Output Current Soft-Start
Optimize Flash Current During Low Battery
Intelligent Flash Current Control
Drives up to 1.5A Output Current
(0.75A per Channel)
High Efficiency PWM Boost Converter
Up to 97% Efficiency with Small Inductor
Under Voltage Lock-Out
Over-Temperature Protection
Over Voltage (Open LED) Protection
LED Short Circuit Protection
Flash Mode and Movie/Torch Mode LEDCurrent can be Programmed via PWM Signalat ENM pin
Flash Mode PWM Dimming Frequency: 1kHzto 200KHz
800mS Flash Timer Control
Cycle by Cycle Current Limit
Separate Hardware Flash and Movie Enable
Set Flash/Movie Currents
Flash Mode Current: 0.75A/Ch Movie Mode Current: 0.40A/Ch
Two Resistors Set Flash and Movie CurrentIndependently
Small Solution Size
Less than 1uA Shutdown Current
RoHS and Green Compliant
14- pin, 2mm X 3mm DFN Packages
-40℃ to +85 ℃ Temperature Range
Applications
Camera Flashes and Movies
Cell Phones or Smart Phones
PDAs and Digital Camera
White LED Biasing
Mobil Handsets
Tablet PCs and Laptops/Netbooks
Camcorder Video Light (Movie Light)
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