English
Language : 

AAT2400 Datasheet, PDF (15/32 Pages) Skyworks Solutions Inc. – Sixteen-Channel White LED Driver Solution
◁
DATA SHEET
AAT2400/2401
Sixteen-Channel White LED Driver Solution
with Full LED Current and Timing Control
PWM Timing
The PWM “on time” of a given current sink is set by the
gray scale and delay registers according to the following
timing diagram. TVSYNC is the period of the VSYNC signal,
typically 1/120 Hz, or 8 1/3 ms, but TVSYNC can be as short
as 500µs. GSCLK is either derived from VSYNC, where FGSCLK
= 4096 x FVSYNC, or supplied by an external signal at the
GSCLK pin. TDLY is the number between 0 and 4095 of the
DLY register, and is the number of GSCLK rising edges
between the rising edge of VSYNC and the rising edge of the
PWM signal. Likewise, TPWM is the number between 0 and
4095 of the GS register, and is the number of GSCLK
periods of the PWM “on time”. The current sink conducts
during the PWM “on time” (shown high in the following
timing diagram). If TPWM is not met by the end of TVSYNC,
the PWM on time will overflow onto the next TVSYNC period.
LED % Brightness = TPWM /4096 x 100.
Device Address Setup
The device address is set by the two address pins,
ADDR1 and ADDR0. Each address pin has four decode
levels resulting in 16 possible address settings. The
address is programmed by connecting ADDR1 and
ADDR0 to VCC, GND, SDI, or by leaving the ADDR pin
unconnected. The master and slave devices can be pro-
grammed with the same device address. The register
addressing will automatically select the appropriate mas-
ter/slave device for the addressed current sink.
VSYNC
1
GSCLK
PWM
TDLY
T VSYNC
TPWM
4096
Device Address
Bit
Bit Name
1:0
ADDR0
3:2
ADDR1
Figure 1: PWM Timing Diagram.
SPI Address:
Addr1 Addr0 Decoding of Address Set Resistors
Description
00: connect to VCC; 01: OPEN; 10: connect to SDI; 11: connect to GND
00: connect to VCC; 01: OPEN; 10: connect to SDI; 11: connect to GND
Table 8: Device Address Settings.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202307A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 24, 2012
15
 ▷