AAT3129
High Efficiency 1X/1.5X/2X Charge Pump
for RGB Color LED Applications
pin has been held high for time TLAT. 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
Applications Information
AS2Cwire Serial Interface
The Advanced Simple Serial Control digital interface
is used to set the color, overall intensity, and method
of update for the R, G, and B channels. The intensi-
ty for each channel is set by dedicated 4-bit registers
giving each channel 16 levels of brightness and
resulting in 4096 possible color combinations. In
addition to the three color registers, there is an inten-
sity register and a mode register. The intensity reg-
ister sets the overall intensity and provides 16 glob-
al brightness levels. The mode register toggles the
method of update between two possibilities.
Depending on the mode register setting, the
AAT3129 will update the R, G, and B channels
immediately or update them only when the intensity
register is updated.
address 1 is signified by 17 rising edges, address 2
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 TLAT timeout
period, a burst of rising edges signifying data, and a
TLAT timeout for the data registers. Once an address
is set, then multiple writes to the corresponding data
register are allowed.
When EN/SET is held low for an amount of time
greater than TOFF, the AAT3129 enters into shut-
down mode and draws less than 1μA from the sup-
ply. Address 1 is the default address on the first ris-
ing edge after the AAT3129 has been disabled.
When shutdown mode is entered, the Address and
Data registers are reset to 1.
AS2Cwire relies on the number of rising edges of the
EN/SET pin to address and load the registers.
AS2Cwire latches data or address after the EN/SET
AS2Cwire Serial Interface Timing
Address
Data
THI
TLAT
TLO
TLAT
EN/SET
1
2
17
1
18
1
2 . . .
n <= 16
2
Address
G
1
1
n
R, B, T, M
AS2Cwire Serial Interface Addressing
Address
EN/SET Rising Edges
Data Register
Description
1
2
3
4
5
17
18
19
20
21
R
G
B
T
Red
Green
Blue
Intensity
Mode
M
10
3129.2007.01.1.4
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
