Diodes: Wide PWM Dimming Extends LED Lamp Dimming Range

The AL8807B is an enhancement of Diodes’ low EMI buck high brightness LED driver AL8807.

The AL8807B provides protection against a number of potential faults within a lamp:

Over-temperature condition: switches itself off
Open-LEDs: automatically stops switching
Short-LEDs: continues switching but at reduced duty cycle minimising power dissipation.

The AL8807B can operate at up to 1MHz – reducing the size of external components. The small MSOP-8EP package size (same footprint as AL8806/7) coupled with the need for only 4 external components produces a small solution footprint.

The accuracy, temperature range, cost and PWM dimming range make it ideally suited to dimmable LED lighting applications.

The Diodes Advantage:

The AL8807B provides a simple wide PWM dimming range solution for Low Voltage general illumination LED lamps.

Simple PWM dimming

Provides a simple solution for varying LED lamps’ brightness with higher accuracy and range than analog dimming

Reduced switching noise and ringing

Reduces EMI issues – especially in non-optimised layout PCBs

Open-LED, short-LED and Over-Temperature Protection Open-LED

automatically stops switching, Short-LED
fSW & duty cycle reduces, TJ > 155ºC
Thermal trip

Small footprint, low thermal impedance packages – MSOP-8EP

High power density small PCB footprint solution

5% initial average LED current accuracy

Meets accuracy requirements of most lighting applications at cost effective price and improves inter-channel matching.

Applications:

General illumination
Multi-substrate LED driving
Driving of parallel LED chains
Wide Analog Dimming LED lamps
12VAC/DC and 24VAC/DC lighting
SELV lighting