D355B Datasheet, PDF (9/14 Pages) List of Unclassifed Manufacturers – Electroluminescent Lamp Driver IC

V. Automatic Turn-Off After Short Time Delay
It is sometimes desirable for the EL lamp to turn off automatically after a few seconds of operation. Typically,
a mechanical switch pulls E’ low to initially turn on the device. When the switch is released, Cdelay keeps
the D355B operating for a short period before turning off. The following table shows typical delay on-
times.
C_delay (µF)
5
7
10
15
20
1.5V
2.4 s
3.3 s
5.1 s
7.2 s
9.9 s
Vbat
3.0V
4.0 s
5.5 s
8.6 s
12.7 s
17.2 s
5.0V
6.0 s
7.8 s
12.5 s
19.3 s
27.0 s
1 GND
E’ 8
2 L-
CLF2 7
CLF
Cdelay
1MΩ
L
3 VOUT CLF1 6
4 L+
V+ 5
D355
1.0µF
Vbat
EL Lamp
VI. Automatic Turn-Off After Long Time Delay
Longer on-times can be achieved with the addition of an external transistor. Typically, a mechanical switch
pulls E’ low to initially turn on the device. When the switch is released, Cdelay keeps the D355B operating
for a period before turning off. The following table shows typical delay on-times using the following circuit
with smaller capacitor values.
Vbat
C_delay (µF)
1
1.5V
9.5 s
3.0V 5.0V
13.0 s 15.6 s
2
17.8 s 24.0 s 29.0 s
3
26.5 s 36.0 s 42.0 s
Vbat
470kΩ
1 _GND
E’ ⁸
2N3904
3.3MΩ
2 _L-
CLF2 7
Cdelay
CLF
L
3 _{VOUT CLF1} 6
4 _{L+ D355 V+ 5}
1.0µF
Vbat
EL Lamp
10