D355B Datasheet, PDF (10/14 Pages) List of Unclassifed Manufacturers – Electroluminescent Lamp Driver IC

VII. High EL Brightness Through Supply Voltage Doubling (Option 1)
Maximum brightness from a D355 is achieved at relatively high supply voltages (>3.0V). An external
voltage boost circuit may be used to increase the voltage supplied to the D355. In the following circuit, the
National Semiconductor LM2665 is used to double the voltage supplied to the D355. This can produce
about twice the brightness of the D355 alone.
NOTE: It is important not to exceed the maximum ratings of either device in this circuit.
3.3µF
Vbat
1 V_BAT CAP+ 6
2 GND OUT 5
1N914
Vbat
3 CAP- SD 4
OFF
LM2665
1 GND
ON
E’ 8
2 L-
CLF2 7
CLF
L
3 VOUT CLF1 6
4 L+
V+ 5
D355
EL Lamp
3.3µF
VIII. High EL Brightness Through Supply Voltage Doubling (Option 2)
In many cases, a resistor may replace the diode in the previous circuit. The diode is used by the LM2665
during startup (see LM2665 datasheet). The circuit below ensures that the LM2665 starts properly before
the D355 is turned on.
NOTE: It is important not to exceed the maximum ratings of either device in this circuit.
3.3µF
Vbat
1 VBAT CAP+ 6
270KΩ
2 GND OUT 5
OFF
Vbat
3 CAP- SD 4
LM2665
ON
1 GND
E’ 8
Vbat
2 L-
CLF2 7
CLF
L
3 VOUT CLF1 6
4 L+
V+ 5
D355
EL Lamp
3.3µF
11