ZXLD1370_1103 Datasheet, PDF (18/36 Pages) Diodes Incorporated – 60V HIGH ACCURACY BUCK/BOOST/BUCK-BOOST LED DRIVER-CONTROLLER WITH AEC-Q100

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Applications Information (Continued)
ZXLD1370 Buck-Boost Mode 350mA Minimum Recommended Inductor
Target Switching Frequency > 500kHz
ZXLD1370
15
13
11
9
L=47µH
7
5
L=33µH
3
L=22µH
1
0
10
20
30
40
50
60
Supply Voltage (V)
Figure 24. 350mA Buck-Boost mode inductor selection for target frequency > 500kHz
For example, in a Buck-bust configuration (VIN =10-18V and 4 LEDs), with a load current of 350mA; if the target frequency
is around 400kHz, the Ideal inductor size is L= 33uH. The same size of inductor can be used if the target frequency is higher
than 500kHz driving 6LEDs with a current of 350mA from a VIN =12-24V.
In the case of the Boost topology, the following graphs guide the designer to select the inductor for a target frequency of
400kHz (figure 25) or higher than 500kHz (figure 26).
ZXLD1370 Boost Mode 350mA Minimum Recommended Inductor
Target Switching Frequency - 400kHz
15
L=47µH
13
11
L=33µH
9
7
L=22µH
5
3
1
0
10
20
30
40
50
60
Supply Voltage (V)
Figure 25. 350mA Boost mode inductor selection for target frequency 400kHz
ZXLD1370
Document number: DS32165 Rev. 4 - 2
18 of 36
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March 2011
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