AL5802LP-7 Просмотр технического описания (PDF) - Diodes Incorporated.
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AL5802LP-7 Datasheet PDF : 10 Pages
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AL5802LP
Application Information (cont.)
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PWM DUTY CYCLE (%)
Figure 15 Typical LED Current Response vs. PWM Duty Cycle for
REXT = 13Ω at 400Hz PWM Frequency
To remove the potential of incorrect connection of the power supply damaging the lamp’s LEDs, many systems use some form of reverse polarity
protection.
One solution for reverse input polarity protection is to simply use a diode with a low VF in-line with the driver/LED combination. The low VF of the
series connected diode increases the available voltage to the LED stack and dissipates less power. A circuit example is presented in Figure 16
using Diodes Inc. SBR® (Super Barrier Rectifier) technology. An SDM10U45LP (0.1A/45V) is shown, providing exceptionally low VF for its package
size of 1mm x 0.6mm, equivalent to an 0402 chip style package. Other reverse voltage ratings are also available on Diodes Inc.’s website such as
the SBR02U100LP (0.2A/100V) or SBR0220LP (0.2A/20V).
Automotive applications commonly use this method for reverse battery protection.
A second approach, shown in Figure 17, improves upon the method shown in Figure 16. Whereas the method in Figure 16 protects the light
engine, it will not function until the problem has been diagnosed and corrected.
The method shown in Figure 17 not only provides reverse polarity protection, it also corrects the reversed polarity, allowing the light engine to
function.
The BAS40BRW incorporates four low VF, Schottky diodes into a single package and allows more voltage available for the LED stack and
dissipates less power than standard rectifier bridges.
SDM10U45LP
VS
BAS40BRW
VS
AL5802LP
RS
Figure 16 Application Circuit for LED Driver
with Reverse Polarity Protection
SBR is a registered trademark of Diodes Incorporated
AL5802LP
Document number: DS37549 Rev. 4 - 2
AL5802LP
RS
Figure 17 Application Circuit for LED Driver with
Assured Operation Regardless of Polarity
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www.diodes.com
March 2016
© Diodes Incorporated
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