AAT3170 Datasheet, PDF (10/15 Pages) Advanced Analogic Technologies – High Current LED Flash Driver Charge Pump IC

AAT3170
High Current LED Flash Driver Charge Pump IC
AS²Cwire latches data or address after the EN/SET
pin has been held high for time T_LAT. Address or
data is differentiated by the number of EN/SET ris-
ing 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 particular
address, followed by a pause with EN/SET held
high for the T_LAT timeout period, a burst of rising
edges signifying data, and a T_LAT timeout for the
data registers. Once an address is set, then multi-
ple writes to that address are allowed where only
data is issued.
When EN/SET is held low for an amount of time
greater than T_OFF, the AAT3170 enters into shut-
down mode and draws less than 1µA from the sup-
ply. Address 0 is the default address on the first ris-
ing 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.
AS²Cwire Serial Interface Addressing
EN/SET
Address Rising Edges
0
17
1
18
2
19
3
20
4
21
5
22
6
23
Data Register
F1 and F2
Current Scale
F1 Current Scale
F2 Current Scale
HI/LO
ON/OFF
Timer
Voltage/Current Mode
HI/LO Scale Register (Address 3)
Data
F1
F2
1
LO
LO
2
HI
HI
3
LO
HI
4
HI
LO
ON/OFF Register (Address 4)
Data
1
2
MODE
ON
OFF
Timer Register (Address 5)
Data
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
On-Time
T (sec) = 10 · C_T (µF)
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
Voltage Register (Address 6)
Data
1
2
MODE
Current
Voltage
Thermal Protection
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.
10
3170.2006.10.1.0