AAT3170
High Current LED Flash Driver Charge Pump IC
AS2Cwire latches data or address after the EN/SET
ON/OFF Register (Address 4)
pin has been held high for time TLAT (500µs).
Address or data is differentiated by the number of
EN/SET rising edges. Since the data registers are
4 bits each, the differentiating number of pulses is
24 or 16, so that Address 0 is signified by 17 rising
edges, Address 1 by 18 rising edges, and so forth.
Data is set to any number of rising edges between
1 and including 16. A typical write protocol is a
burst of EN/SET rising edges, signifying a particu-
lar address, followed by a pause with EN/SET held
high for the TLAT timeout period, a burst of rising
edges signifying data, and a TLAT timeout for the
data registers. Once an address is set, then multi-
ple writes to that address are allowed where only
data is issued.
Data
MODE
1
2
ON
OFF
Timer Register (Address 5)
On-Time
T (sec) = 10 · CT (µF)
Data
1
2
16/16 x T
15/16 x T
14/16 x T
13/16 x T
12/16 x T
11/16 x T
10/16 x T
9/16 x T
8/16 x T
7/16 x T
6/16 x T
5/16 x T
4/16 x T
3/16 x T
2/16 x T
1/16 x T
3
4
5
6
When EN/SET is held low for an amount of time
greater than TOFF (500µs), the AAT3170 enters into
shutdown mode and draws less than 1µA from the
supply. Address 0 is the default address on the first
rising edge after the AAT3170 has been disabled.
After shutdown, if only data is issued with the first
rising edge (i.e., 1 - 16 edges, no address given),
both current sinks will be programmed since the
default will be Address 0.
7
8
9
10
11
12
13
14
15
16
AS2Cwire Serial Interface Addressing
EN/SET
Address Rising Edges
Voltage Register (Address 6)
Data Register
0
17
F1 and F2
Current Scale
F1 Current Scale
F2 Current Scale
HI/LO
Data
MODE
1
2
Current
Voltage
1
2
3
4
5
6
18
19
20
21
22
23
Thermal Protection
ON/OFF
The AAT3170 has a thermal protection circuit that
will shut down the charge pump if the die tempera-
ture rises above the thermal limit, as is the case
during a short circuit of the OUT pin.
Timer
Voltage/Current Mode
HI/LO Scale Register (Address 3)
Data
F1
F2
1
2
3
4
LO
HI
LO
HI
LO
HI
HI
LO
10
3170.2006.11.1.1
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
