D355B Datasheet, PDF (8/14 Pages) List of Unclassifed Manufacturers – Electroluminescent Lamp Driver IC

III. Two-Level Dimming
Toggle switching between two different EL lamp brightness levels may be achieved with the following
circuit. When DIM is low, the external pnp transistor is saturated and the EL lamp runs at full brightness.
When DIM is high, the external pnp turns off and the 47Ω resistor reduces the voltage at (V+) and dims the
EL lamp.
1 GND
2 L-
E’ 8
CLF2 7
OFF
ON
E’
CLF
DIM
Low B
High B
1kΩ
L
3 VOUT CLF1 6
2N3906
4 L+
V+ 5
D355
47Ω
1.0µF
Vbat
EL Lamp
IV. Lamp Frequency Control with an External Clock Signal
An external clock signal with a 50% duty cycle may be used to control the EL lamp frequency (LF). This
technique allows the designer flexibility to synchronize the El driver IC with other elements in the application.
The output lamp frequency will be the same frequency as the input clock signal. For example, if a 250Hz
input clock signal is used, the resulting lamp frequency will be 250Hz. The clock signal voltage should not
exceed V+.
1 GND
E’ 8
OFF
ON
2 L-
CLF2 7
Lamp Frequency CLK
L
3 VOUT CLF1 6
150kΩ
1.0V Min
0.2V Max
4 L+
V+ 5
D355
1.0µF
Vbat
EL Lamp
9