AAT3129_07 Datasheet, PDF (10/15 Pages) Advanced Analogic Technologies – High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications

AAT3129
High Efficiency 1X/1.5X/2X Charge Pump
for RGB Color LED Applications
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.
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
pin has been held high for time T_LAT. 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 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 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 multiple writes to the corresponding data
register are allowed.
When EN/SET is held low for an amount of time
greater than T_OFF, 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 Serial Interface Timing
EN/SET
Address
Address
T_HI
T_LO
T _LAT
1
2
17
18
1
Data
T _LAT
1
2 . . . n <= 16
2
G
1
n
R, B, T, M
1
AS²Cwire Serial Interface Addressing
Address
1
2
3
4
5
EN/SET Rising Edges
17
18
19
20
21
Data Register
R
G
B
T
M
Description
Red
Green
Blue
Intensity
Mode
10
3129.2007.01.1.4