Diodes AL8843EV1 User Manual

AL8843EV1 User Guide

Parameter

Value

Input Voltage

5VDC to 40VDC

LED Current

2A

Number of LEDs

1~10 LEDs

XYZ Dimension

63mm x 40mm x 10mm

General Description

The AL8843 is a hysteresis mode DC-DC
step-down converter, designed for driving
single or multiple series connected LEDs
efficiently from a voltage source higher
than the LED voltage. The device can
operate from an input supply between 4.5V
and 40V and provide an externally
adjustable output current up to 3A.
Depending upon supply voltage and
external components, this converter can
provide up to 60W of output power.

The AL8843 integrates the power switch
and a high-side output current sensing
circuit, which uses an external resistor to
set the nominal average output current.
Dimming can be realized by applying an
external control signal to the CTRL Pin. The
CTRL Pin will accept either a DC voltage
signal or a PWM signal.

The soft-start time can be adjusted by an
external capacitor from the CTRL Pin to
Ground. Applying a voltage of 0.3V or lower
to the CTRL Pin will shut down the power
switch.

Applications

 LED Retrofit for Low Voltage Halogen
 Low Voltage Industrial Lighting
 LED Backlighting
 Illuminated Signs
 External Driver with Multiple Channels

Key Features

 Wide Input Voltage Range: 4.5V to 40V
 Output Current up to 3A
 Internal 40V NDMOS Switch
 Typical 4% Output Current Accuracy
 Single Pin for On/Off and Brightness

Control by DC Voltage or PWM Signal

 Recommended Analog Dimming Range:

10% to 100%

 Soft-Start
 High Efficiency (Up to 97%)
 LED Short Protection
 Inherent Open-Circuit LED Protection
 Over Temperature Protection (OTP)
 Up to 1MHz Switching Frequency
 SO-8EP Packages Available in Green

Molding Compound (No Br, Sb)

AL8843EV1 Specifications

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Dec 2017

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AL8843EV1 User Guide

Figure 1: Top View

Connection Instructions

Power Supply Input: 5~40VDC (VIN, GND)
CTRL: Internal voltage ref. pin (2.5V). This pin can be used to achieve dimming and for switching
the output current off. Leave floating for normal operation.
PWM Signal Input: Remove C4, apply PWM signal to CTRL (CTRL, GND)
Analog Signal Input: Connect 470nF capacitor to C4, apply analog signal to CTRL (CTRL, GND)
LED A: LED A connects to the external LED anode
LED K: LED K connects to the external LED cathode

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Figure 2: Bottom View

AL8843EV1 User Guide

Evaluation Board Schematic

Figure 3: Evaluation Board Schematic

AL8843EV1 Page 3 of 10
Dec 2017

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