ZXLD1370_11 DIODES [Diodes Incorporated], ZXLD1370_11 Datasheet - Page 18

• Manufacturer Part Number: ZXLD1370_11
• Description: 60V HIGH ACCURACY BUCK/BOOST/BUCK-BOOST LED DRIVER CONTROLLER
• Manufacturer: DIODES [Diodes Incorporated]

ZXLD1370
Document number: DS32165 Rev. 3 - 2
Applications Information
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).
Figure 24. 350mA Buck-Boost mode inductor selection for target frequency > 500kHz
15
13
11
15
13
11
Figure 25. 350mA Boost mode inductor selection for target frequency 400kHz
9
7
5
3
1
9
7
5
3
1
0
0
L=22uH
L=22uH
10
10
(Continued)
ZXLD1370 Buck-Boost Mode 350mA Minimum Recommended Inductor
ZXLD1370 Boost Mode 350mA Minimum Recommended Inductor
L=33uH
L=33uH
20
20
Target Switching frequency > 500kHz
Target Switching frequency - 400kHz
L=47uH
Supply Voltage (V)
Supply Voltage (V)
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L=47uH
30
30
40
40
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50
50
60
60
© Diodes Incorporated
ZXLD1370
February 2011