CRD1611-8W
1. INTRODUCTION
The CS1611 is a 230VAC quasi-resonant flyback mode dimmable LED controller IC. The CS1611 uses a digital con-
trol algorithm that is optimized for high efficiency and >0.9 power factor over an input voltage range (207VAC to
253VAC). The CS1611 integrates a critical conduction mode (CRM) boost converter that provides power factor cor-
rection and dimmer compatibility with a constant output current, quasi-resonant flyback stage. An adaptive dimmer
compatibility algorithm controls the boost stage and dimmer compatibility operation mode to enable flicker-free op-
eration to <2% output current with leading-edge, trailing-edge, and digital dimmers.
The CRD1611-8W board is optimized to deliver low system cost in a high-efficiency, flicker-free, phase-dimmable,
solid-state lighting (SSL) solution for incandescent lamp replacement applications. The feedback loop is closed
through an integrated digital control system within the IC. The variation in switching frequency also provides a
spread-frequency spectrum, thus minimizing the conducted EMI filtering requirements. Protection algorithms such
as output open/short, current-sense resistor open/short, and overtemperature thermistors protect the system during
abnormal conditions. Details of these features are provided in the CS1611 data sheet.
The CRD1611-8W board demonstrates the performance of the CS1611. This reference board has been designed
for an output load of 4LEDs in series at 550mA (12.0V typical).
This document provides the schematic for the board. It includes oscilloscope screen shots that indicate various op-
erating waveforms. Graphs are also provided that document the performance of the board in terms of Efficiency vs.
Line Voltage, Output Current vs. Line Voltage, and Output Current vs. Dim Angle for the CS1611 dimmable LED
controller IC. Extreme caution needs to be exercised while handling this board. This board is to be used by trained
professionals only.
DS975RD5
3
CIRRUS [ CIRRUS LOGIC ]
