Rainbow Electronics MAX6975 - Manual (Page 6)

MAX6974/MAX6975
24-Output PWM LED Drivers
for Message Boards
6 _______________________________________________________________________________________
MAX6974 Block Diagram
R LED DRIVERS
R7–R0
I SET
R7
I SET
8-BIT
G CALDAC
MUX1
OUTPUTS
7-BIT GLOBAL-INTENSITY PDM MODULATOR
12-BIT INDIVIDUAL PWM MODULATOR
8 8
288
CALIBRATION
DATA LATCH
GLOBAL-
INTENSITY
DATA LATCH
8 8
MUX0 PIXEL PWM NEW DATA LATCH MUX1 PIXEL PWM NEW DATA LATCH
288 288
EXT. PNP EXT. PNP
7
7
EN EN
PWM
COUNTERS
SYNC
288-BIT DATA SHIFT REGISTER
CLKI
LOADI
D
CLKO
DOUT
DIN
288
288
288
CONTROL
MUX0 PIXEL PWM OLD DATA LATCH
LOAD
288 288
MUX1 PIXEL PWM OLD DATA LATCH
OE
LOAD
Q1
24
7
MUX0
OUTPUT
24-BIT NEW HEADER
SHIFT REGISTER
SYNC DETECT
R6 R5 R4 R3 R2 R1 R0
8-BIT
R CALDAC
R LED OUTPUTS
G LED DRIVERS
G7–G0
G7 G6 G5 G4 G3 G2 G1 G0
G LED OUTPUTS
LOADO
I SET
8-BIT
B CALDAC
8
B LED DRIVERS
B7–B0
B7 B6 B5 B4 B3 B2 B1 B0
B LED OUTPUTS
8
0/1
OE
MAX6974