AW36414CSR datasheet(20/39 Pages) AWINIC

20 / 39 page

AW36414

Jan 2018 V1.3

www.awinic.com.cn

capacitor reaches 2.2 V (typical) the current source turns on. At turn-on the current source steps through each

FLASH or TORCH level until the target LED current is reached. This gives the device a controlled turn-on and

limits inrush current from the VIN supply.

PASS MODE

The AW36414 starts up in Pass Mode and stays there until Boost Mode is needed to maintain regulation. In

Pass Mode the boost converter does not switch, and the synchronous PMOS turns fully on bringing VOUT up to

VIN

− ILED × RPMOS. In Pass Mode the inductor current is not limited by the peak current limit. If the voltage

difference between VOUT and VLED falls below VHR, the device switches to Boost Mode.

POWER AMPLIFIER SYNCHRONIZATION (TX)

The TX pin is a Power Amplifier Synchronization input. This is designed to reduce the flash LED current and

thus limit the battery current during high battery current conditions such as PA transmit events. When the

AW36414 is engaged in a Flash event, and the TX pin is pulled high, the LED current is forced into Torch

Mode at the programmed Torch current setting. If the TX pin is then pulled low before the Flash pulse

terminates, the LED current returns to the previous Flash current level. At the end of the Flash time-out,

whether the TX pin is high or low, the LED current turns off.

The TX input can be disable by setting bit[7] (TX Enable) to a

‘0’ in the Enable Register(0x01).

INPUT VOLTAGE FLASH MONITOR (IVFM)

The AW36414 has the ability to adjust the flash current based upon the voltage level present at the IN pin

utilizing the Input Voltage Flash Monitor (IVFM). The adjustable threshold ranges from 2.9 V to 3.6 V in

100mV steps as well as adjustable hysteresis, with three different usage modes (Stop and Hold, Down, Up

and Down). The IVFM threshold and hysteresis are controlled by bits[5:3] and bit[2] respectively, in the IVFM

threshold value. Additionally, the IVFM threshold sets the input voltage boundary that forces the AW36414 to

either stop ramping the flash current during startup in Stop and Hold Mode, or to actively adjust the LED

current lower in Down Mode, or to continuously adjust the LED current up and down in Up & Down Mode.

 Stop and Hold Mode: Stops Current Ramp and holds the level for the remaining flash, If VIN falls below the

IVFM threshold value.

 Down Mode: Adjust current down if VIN falls below the IVFM threshold value and stops decreasing once VIN

rises above the IVFM threshold (or plus a hysteresis). The AW36414 will decrease the current throughout

the flash pulse anytime VIN falls below the IVFM threshold, not just once. The flash current will not increase

again until the next flash.

 Up & Down Mode: Adjust current down if VIN falls below the IVFM threshold value and adjusts current up if

VIN rise above the IVFM threshold (or plus a hysteresis). In Up & Down mode, the LED current will

continually adjust with the rising and falling of VIN throughout the entire flash pulse.

AW36414CSR Datasheet(PDF) 20 Page - Shanghai awinic technology co.,ltd