AL5802

30V, ADJUSTABLE CURRENT SINK LINEAR LED DRIVER

AL5802

Document number: DS35516 Rev.4 - 2

9 of 11

www.diodes.com

November 2011

© Diodes Incorporated

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

less power. A circuit example is presented in Fig. 18 using Diodes

Inc. SBR® (Super Barrier Rectifier) technology. An SDM10U45LP

size of 1mm x 0.6mm, equivalent to an 0402 chip style package.

Other reverse voltage ratings are also available in Diodes’ 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 Fig. 19, improves upon the method

shown in Fig. 18. Whereas the method in Fig. 18 protects the light

engine, it will not function until the problem has been diagnosed and

corrected.

The method shown in Fig. 19 not only provides reverse polarity

protection, it also corrects the reversed polarity, allowing the light

engine to function.

single package and allows more voltage available for the LED stack

and dissipates less power that standard rectifier bridges.

Fig. 18 Application circuit for LED driver

with reverse polarity protection

Fig. 19 Application circuit for LED driver with

assured operation regardless of polarity

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SBR is a registered trademark of Diodes Incorporated.