AS3647 datasheet(2/38 Pages) AMSCO

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AS3647/47B

1600mA High Current LED Flash Driver

www.austriamicrosystems.com/AS3647

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Datasheet

1 General Description

The AS3647/47B is an inductive high efficient DCDC

step up converter with two current sinks. The DCDC

step up converter operates at a fixed frequency of 4MHz

and includes soft startup to allow easy integration into

noise sensitive RF systems. The two current sinks can

operate in flash / torch / assist (=video) light modes.

The AS3647/47B includes flash timeout, overvoltage,

overtemperature, undervoltage and LED short circuit

protection functions. A TXMASK/TORCH function

reduces the flash current in case of parallel operation to

the RF power amplifier and avoids a system shutdown.

Alternatively this pin can be used to directly operate the

torch light directly.

The AS3647/47B is controlled by an I

2C interface and

has a hardware automatic shutdown if SCL=0 for

100ms. Therefore no additional enable input is required

for shutting down of the device once the system shuts

down.

The AS3647/47B is available in a space-saving WL-

CSP package measuring only 2.25x1.5x0.6mm

(AS3647B: 2.25x1.5x0.5mm) and operates over the -

30ºC to +85ºC temperature range.

Figure 1. Typical Operating Circuit

2 Key Features



High efficiency 4MHz fixed frequency DCDC Boost

converter with soft start allows small coils

- Stable even in coil current limit



LED current adjustable up to 1600mA



Automatic current adjustment for low battery voltage



PWM operation for lower output current for reliable

light output of the LED; running at 31.25kHz to avoid

audible noise



Protection functions:

Automatic Flash Timeout timer to protect the LED(s)

Overvoltage and undervoltage Protection

Overtemperature Protection

LED short/open circuit protection



2C Interface with automatic shutdown



5V constant voltage mode operation



Available in tiny WL-CSP Packages, 13 balls 0.5mm

pitch 2.25x1.5x0.6mm, 15 balls 0.4mm pitch

2.25x1.5x0.5mm package size

3 Applications

Flash/torch/videolight for smartphones, feature-phones,

tablets, DSCs, DVCs

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