AL8805

HIGH EFFICIENCY 30V 1A BUCK LED DRIVER

AL8805

Document number: DS35030 Rev. 1 - 2

13 of 16

www.diodes.com

September 2010

© Diodes Incorporated

Figure 35. Recommended PCB Layout

Application Example

Typical

application

example

for

the

AL8805

is

the

using

conventional

electromagnetic

transformers

or

electronic transformers.

As a replacement in some halogen lamp applications LEDs

offer a more energy efficient solution – providing no radiated

heat and no Ultra Violet light.

This application example is intended to fit into the base

connector space of an MR16 style LED lamp. The design

has been optimized for part count and thermal performance

for a single 3W LED in the Lens section.

AL8805

AL8805

Figure 36. MR16 Schematic

An inductor choice of 33µH with saturation current higher

than 1.1A, will limit the frequency variation between 230kHz

and 350kHz over the whole input voltage variation (8V to

18V), and therefore represent the best choice for an

MR16 solution also taking into account the size constraint of

the lamp.

The AL8805 guarantee high level of performance both with

The efficiency is generally higher than 81% and current

regulation is better than 0.1mA/V in for a DC input voltage in

the range from 8V to 18V.

In table 1 can be found the bill of material of the

MR16 application example.

In figures 37 and 38 are displayed the top layer and the

bottom layer of a typical PCB design for an MR16 solution.

Figure 37. Top Layer

Figure 38. Bottom Layer