PRODUCT DATASHEET
AAT3170
ChargePumpTM
High Current LED Flash Driver Charge Pump IC
LO scale by just giving a single burst of data edges. The
address edges are not needed because all registers are
reset during shutdown and address 0 is the default.
Further, a single burst of data edges can be used to
change from one setting to another for the last address.
The address register is not reset after each write; there-
fore, submitting address edges is only required when
changing the address.
Applications Information
AS2Cwire Programming
Generally, programming the AAT3170 is achieved by
submitting bursts of address and data edges to the EN/
SET pin. However, in some cases multiple bursts of
address and data are needed to enable a particular oper-
ating mode. In other cases, only a single burst of data
edges is required.
Additional Applications
To enable both flash channels to a current setting on the
LO scale, the user submits a single burst of address and
data edges. To enable both flash channels to a current
setting on the HI scale, the user must submit a burst of
address and data edges to program the current setting
level, and then submit a second burst of address and
data edges to program the HI/LO scale register to the HI
scale.
The constant voltage mode feature of the AAT3170
allows the user to combine the flash feature with addi-
tional applications. Additional applications such as auxil-
iary lighting and status LEDs can be added while elimi-
nating the need for an additional power supply, which is
normally required. Since the constant voltage mode can
supply a regulated output at up to 200mA load, it is
capable of driving ten LEDs at 20mA each. It is suitable
for keypad lighting, status lighting, and other applica-
tions where a 4.5V power supply could be used.
Shortcuts can also be used. If the device is in shutdown,
both flash channels can be enabled to a setting on the
C1
1μF
C2
1μF
C1+
C1- C2+
C2-
2.7V to 5.5V
EN/SET
VIN
VOUT
CIN
4.7μF
COUT
2.2μF
Flash
LED
AAT3170
EN/SET
CT
F1
F2
AUX_EN
GND
Figure 1: Flash Plus Auxiliary Lighting.
C1
1μF
C2
1μF
C1+
C1- C2+
C2+
2.7V to 5.5V
EN/SET
VIN
VOUT
CIN
4.7μF
COUT
2.2μF
Flash
LED
AAT3170
EN/SET
CT
F1
F2
STAT1
STAT2
GND
Figure 2: Flash Plus Status Lighting.
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