MAX6947 Maxim Integrated Products, MAX6947 Datasheet - Page 14

• Manufacturer Part Number: MAX6947
• Description: Constant-Current LED Drivers and I/O Expanders
• Manufacturer: Maxim Integrated Products

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Table 8. Ramp-Down Register Format (0X11)
10-Port, Constant-Current LED Drivers and
I/O Expanders with PWM Intensity Control
Figure 6. Output Fade DAC (Global Current = 0x07)
14
Instant going into shutdown after hold-off delay
1/16s ramp-down from full current before shutdown after hold-off delay
1/8s ramp-down from full current before shutdown after hold-off delay
1/4s ramp-down from full current before shutdown after hold-off delay
1/2s ramp-down from full current before shutdown after hold-off delay
1s ramp-down from full current before shutdown after hold-off delay
2s ramp-down from full current before shutdown after hold-off delay
4s ramp-down from full current before shutdown after hold-off delay
Zero hold-off delay before fade-off going into shutdown
1/16s hold-off delay before fade-off going into shutdown
1/8s hold-off delay before fade-off going into shutdown
1/4s hold-off delay before fade-off going into shutdown
1/2s hold-off delay before fade-off going into shutdown
1s hold-off delay before fade-off going into shutdown
2s hold-off delay before fade-off going into shutdown
4s hold-off delay before fade-off going into shutdown
CURRENT
17.5mA
12.5mA
7.5mA
2.5mA
20mA
15mA
10mA
0mA
5mA
______________________________________________________________________________________
PORT CURRENT = FULL
PORT CURRENT = HALF
CURRENT
FULL
FADE-UP
CURRENT
7/8
CURRENT
6/8
CURRENT
5/8
DESCRIPTION
CURRENT
4/8
CURRENT
3/8
CURRENT
FADE-OFF
2/8
CURRENT
1/8
CURRENT
ZERO
The ramp-down register sets the hold-off and fade-off
times and allows disabling of hold-off and fade-off (zero
delay), if desired (Table 8). The ramp-up register sets
the ramp-up time and allows disabling of ramp-up (zero
delay), if desired (Table 9). The configuration register
contains three status bits that identify the condition of
the MAX6946/MAX6947, hold-off, fade-off, or ramp-up
(Table 2). The configuration register also enables or dis-
ables ramp-up. One write command to the configuration
register can put the MAX6946/MAX6947 into shutdown
(using hold-off and fade-off settings in the fade register)
and one read command to the configuration register can
determine whether the Reset Run is enabled for restart,
and whether the MAX6946/MAX6947 will use ramp-up
on restart.
D7
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
D6
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
D5
X
X
X
X
X
X
X
X
0
0
0
0
1
1
1
1
REGISTER BIT
D4
X
X
X
X
X
X
X
X
0
0
1
1
0
0
1
1
D3
X
X
X
X
X
X
X
X
0
1
0
1
0
1
0
1
D2
0
0
0
0
1
1
1
1
X
X
X
X
X
X
X
X
D1
X
X
X
X
X
X
X
X
0
0
1
1
0
0
1
1
D0
0
1
0
1
0
1
0
1
X
X
X
X
X
X
X
X