D365A Datasheet, PDF (7/12 Pages) List of Unclassifed Manufacturers – Electroluminescent Lamp Driver IC

II. Inductor (L) Selection
The external inductor (L) selection for a D365A circuit greatly affects the output capability and current draw of the
driver. A careful designer will balance current draw considerations with output performance in the choice of an ideal
inductor for a particular application. Figures 3 and 4 show typical brightness and current draw of a D365A circuit with
different inductor values, lamp sizes, and supply voltages while keeping HF and LF constant. Please note that the DC
resistance (DCR) of inductors with the same nominal inductance value may vary with manufacturer and inductor type.
Thus, inductors made by a different manufacturer may yield different outputs, but the trend of the different curves
should be similar. Lamp luminance is also a function of lamp size. In each example, a larger lamp will have less
luminance with approximately the same current draw.
8
80
7
Luminance
Current
70
6
60
5
50
4
40
3
30
2
20
1
10
0
0
0
1
2
3
4
5
6
7
8
Inductor (mH)
Figure 3: Brightness and current vs. inductor value.
(Conditions: V+ = 3.3V, 2 in² EL Lamp)
8
80
7
Luminance
70
6
Current
60
5
50
4
40
3
30
2
20
1
10
0
0
0
1
2
3
4
5
6
7
8
Inductor (mH)
Figure 4: Brightness and current vs. inductor value.
(Conditions: V+ = 5.0V, 4 in² EL Lamp)
7