2500mA High Current Flash LED Driver
The AS3649 is an inductive high efficient DCDC step up converter with two current sources and operates at a fixed frequency of 4MHz. It includes soft startup to allow easy integration into noise sensitive RF systems. The two current sources can operate in flash / torch or video light modes. The AS3649 includes flash timeout, overvoltage, overtemperature, undervoltage and LED short/open circuit protection functions.
A TXMASK/TORCH function reduces the flash current in case of parallel operation to the RF power amplifier to protect the system from unwanted shutdown. Alternatively this pin can be used to directly operate the torch light directly. If the TXMask function is not used, it can be used as a hardware torch input (programmable). A hardware NTC pin can be used to measure the LED temperature with the ADC and to automatically reduce the LED current if a temperature threshold is exceeded.
The AS3649 is controlled by an I2C interface and has a dedicated hardware reset pin. The interface input voltage levels are 1.8V compliant.
The AS3649 is available in a space-saving WL-CSP package measuring only 2.06 x 2.02 x 0.6 mm and operates over the -30ºC to +85ºC temperature range.
- 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 2x1000mA(2x1250mA with current boost) or 2000mA and automatic load balancing for two LEDs
- Automatic current adjustment for low battery voltage
- PWM operation for lower output current for reliable light output of the LED; can run at 31.5kHz to avoid audible noise
- Various protection functions:
- Automatic flash timeout timer to protect the LED(s)
- Overvoltage and undervoltage protection
- Overtemperature protection
- LED short/open circuit protection
- ADC to measure LED temperature
- NTC to automatically reduce the flash current if the LED temperature is too high (programmable level)
- I2C Interface with hardware reset pin
- Tiny WL-CSP package and high integration enables lowest space system designs
- Flash, torch for mobile phones
- Tablet PCs
- Other handheld battery driven devices which uses a camera
AS3649 cameraflash LED driver block diagram