AW3643

Jan 2018 V1.4

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21

Copyright © 2016 SHANGHAI AWINIC TECHNOLOGY CO., LTD

Flash Event

VIN

VIN

VIN

Flash Current

Flash Current

Flash Current

Hysteresis = 0 or 50mV

Target Flash Current

IVFM-Threshold

IVFM-Threshold

IVFM-Threshold

Flash Current with

IVFM Disable

Stop & Hold

Mode

Down

Mode

Up & Down

Mode

Hysteresis = 0 or 50mV

Fig 50

IVFM Modes

FLASH TIMEOUT

The Flash Timeout period sets the maximum time of one flash event, whether a flash stop command is

received or not. The AW3643 has 16 timeout levels ranging from 40ms to 1.6s (see TIMING

CONFIGURATION REGISTER (0X08) for more detail). Flash Timeout applies to both Flash and IR modes,

and it continues to count when the Flash mode is forced into Torch mode during a TX high event. The mode

bits are cleared and bit[0] is set in the Flags1 register(0x0A) upon a Flash Timeout. This fault flag can be reset

to '0' by reading back the Flags1 Register (0x0A), or by setting HWEN to '0', or by setting the SW RESET bit

to a '1', or by removing power to the AW3643.

CURRENT LIMIT

When the inductor current limit is reached, the AW3643 terminates the charging phase of the switching cycle

until the next switching period. If the over-current condition persists, the device operates continuously in

current limit. The AW3643 features two selectable inductor current limits(1.9A and 2.8A) that are

programmable by bit[0] in Boost configuration Register(0x07).

Since the current limit is sensed in the NMOS switch, there is no mechanism to limit the current when the

device operates in Pass Mode (current does not flow through the NMOS in pass mode). The mode bits are

not cleared upon a Current Limit event, but a flag bit[3] is set in the Flags1 register(0x0A).