SLR2016, SLO2016, SLG2016, SLY2016, SCD5584A
Dimming Circuit Using a 556 and Dimming
(Blanking) Timing
Typical Loading State Table
WR A1 A0 D6 D5 D4 D3 D2 D1 D0 Digit
VCC = 5 V
3
2
1
0
Dimming (Blanking)
Control
H
L
L
L
L
L
L
L
previously loaded display
G
G
G
G
B
B
B
R
R
R
L
E
E
U
U
U
E
E
Y
E
E
E
E
E
W
R2
47 k
Ω
Ω
L
L
H
H
H
H
H
H
L
L
L
L
L
L
L
H
L
L
L
H
L
L
H
L
L
L
H
H
H
L
L
L
L
H
L
H
H
H
L
R3
1
2
3
4
5
6
7
14
13
12
11
10
9
500 k
Ω
R1
200
L
H
L
H
H
L
C3
1000 pF
H
H
L
L
L
C2
0.01 µF
H
H
H
H
L
556
Dual Timer
L
L
C4
0.01 µF
X
X
see character code
see char. set
To BL Pin
on Display
Display Blanking
C1
4700 pF
Blank the display by loading a blank or space into each digit of the
display or by using the (BL) display blank input. Setting the (BL)
input low does not affect the contents of data memory.
8
A flashing circuit can easily be constructed using a 555 as table
multivibrator. Figure 3 illustrates a circuit in which varying R1
(100K~10K) will have a flash rate of 1.0 Hz~10 Hz.
IDCD5034
1
0
The display can be dimmed by pulse width modulating the (BL) at
a frequency sufficiently fast to not interfere with the internal clock.
The dimming signal frequency should be 2.5 kHz or higher. Dim-
ming the display also reduces power consumption.
Blanking Pulse Width
4 µs min., 196 µs max.
~
200 µs
~
An example of a simple dimming circuit using a 556 is illustrated in
Figure 4. Adjusting potentiometer R3 will dim the display by chang-
ing the blanking pulse duty cycle.
~
~
5 kHz Blanking Frequency
IDCD5036
Flashing Circuit Using a 555 and Flashing
(Blanking) Timing
VCC = 5 V
R1
4.7 k
1
2
3
4
8
7
6
5
Ω
R2
100 k
555
Timer
Ω
To BL
Pin on
Display
C3
10 µF
C4
0.01 µF
IDCD5033
1
0
~
500 ms
~
Blanking Pulse Width
~
~
50% Duty Factor
~
2 Hz Blanking Frequency
~
IDCD5035
2006-01-23
5
OSRAM [ OSRAM GMBH ]
