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FUNCTIONAL BLOCK DIAGRAM
Control Logic
/Regsiter
UVLO
OSC
2/4Mhz
IVFM
NTC
monitor
I
2
C
Interface
Thermal Shutdown
Protection
FB
Select
OUT
LED1
LED2
SW
IN
GND
Boost Controller
OVP
V
OVP
Current
Limit
TORCH/TEMP
SDA
SCL
I
NTC
=50uA
LED & OUT
Short Detect
AW3643
TX
HWEN
STROBE
FEATURE DESCRIPTION
HWEN & I
2
C INTERFACE
AW3643 has a logic input HWEN pin to enable/disable the device. When HWEN is set low, the device goes
into shutdown mode, the I
2
C interface is disabled and all I
2
C registers are reset to default. In shutdown mode
the device does not respond to any I
2
C command. When HWEN is set high, the device goes into standby
mode, the I
2
C interface is enabled, and the device can respond to I
2
C command.
There are two kinds of power-up sequences, shown in Figure 45 and Figure 46.
If HWEN is tied to IN pin in application, once IN goes above around V
POR
(2.0V), HWEN should stay high for at
least t
wait
=2ms time before any I
2
C command can be accepted.
If HWEN is driven by a GPIO, once HWEN goes from low to high, HWEN should stay high for at least
t
wait
=2ms time before any I
2
C command can be accepted.
HWEN=IN
I
2
C command
t
wait
≥2ms
Fig 45 Power-Up Sequence with HWEN Tied to IN
