AL8805EV2

Issue 1 – August 2010

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© Diodes Incorporated 2010

5

AL8805EV2 Basic operation at full voltage

1.

Connect P1 and P2 to the power supply

2.

Set the PSU to 12VAC or 12VDC

3.

Turn on the PSU and the LED will illuminate and the current should be approximately 680mA.

Warning: Do not stare at the LED directly.

Changing the LED current

1.

Remove R1.

2.

Calculate and fit a new sense resistor, R1, the value of which is based on the required LED

current without dimming. R1 can be calculated using following equation :

R1 = the sense resistor value in ohms.

0.1V is the nominal sense voltage with ‘CTRL’ open circuit or set to 2.5V.

An on-line Calculator is available to speed up the design process at:

http://www.diodes.com/destools/calculators.html

PERFORMANCE

The system efficiency depends on the sense resistor, supply voltage, switching inductor and the

number of LEDs.

With a 12VDC supply, the switching frequency is typically 300kHz, and the efficiency level is >80% .

For further advice, please contact our local FAE or contact our local sales offices as listed

below.