Cirrus Logic AN405 - Manual (Page 3)

AN405
3
1. INTRODUCTION
The CS1680 is a cascade boost-buck dimmable LED controller IC. The CS1680 uses a Cirrus Logic proprietary in-
telligent digital control that provides exceptional single-lamp and multi-lamp transformer compatibility for non-dim-
mer systems and dimmer systems paired with electronic and magnetic low-voltage transformers. The CS1680
integrates a continuous conduction mode (CCM) boost converter that provides transformer compatibility and dimmer
compatibility with a constant output current buck stage. An adaptive dimmer compatibility algorithm controls the
boost stage and dimmer compatibility operation mode to enable flicker-free operation down to 5% output current with
leading-edge and trailing-edge dimmers.
The CRD1680-10W-18V board is optimized to deliver low system cost in a high-efficiency, flicker-free, phase-dim-
mable, solid-state lighting (SSL) solution for incandescent lamp replacement applications. The feedback loop is
closed through an integrated digital control system within the IC. Protection algorithms such as output open/short,
overcurrent detection, boost overvoltage, and overtemperature thermistors protect the system during abnormal con-
ditions. Details of these features are provided in the CS1680 data sheet.
The CRD1680-10W-18V board demonstrates the performance of the CS1680. This reference board has been de-
signed for an output load of 6xLEDs in series at 430mA (
 18V typical).
This data sheet provides the schematic and PCB layout for the reference design board. The performance graphs
demonstrate the performance of the CS1680 dimmable-controller reference design in terms of Efficiency vs. Line
Voltage, Power Factor vs. Line Voltage, THD vs. Line Voltage, and Output Current vs. Line Voltage.
Extreme caution needs to be exercised while handling this board. This board is to be used by trained professionals
only.