Cirrus Logic AN405 User Manual
CRD1680-10W-18V Schematic
AN405
Design Example of CS1680
for 10W Dimmer-Compatible SSL Circuit
Features
• Constant-current Output
• Flicker-free Dimming
• Line Voltage: 12 VAC/VDC, +/- 10%
• Rated Input Power: 10W
• Rated Output Power: 7.8W
• Efficiency: ~82% at 430mA for 6xLEDs in Series
• Low Component Count
General Description
This application note provides an example of a Solid State
Lighting (SSL) LED lamp circuit designed using Cirrus
Logic’s CS1680, the CRD1680-10W-18V. The CRD168010W-18V reference design demonstrates the performance
of the CS1680 dimmable LED driver for low-voltage lighting
with a 430mA output driving
exceptional single-lamp and multi-lamp transformer
compatibility for non-dimmer systems and dimmer systems
paired with electronic and magnetic low-voltage
transformers. The form factor is targeted to fit into MR16
LED lamp applications.
6xLEDs in series
. It provides
Cirrus Logic, Inc.
http://www.cirrus.com
Copyright Cirrus Logic, Inc. 2014
(All Rights Reserved)
OCT‘14
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Contacting Cirrus Logic Support
For all product questions and inquiries contact a Cirrus Logic Sales Representative. To find the one nearest to you
go to www.cirrus.com
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IMPORTANT SAFETY INSTRUCTIONS
Read and follow all safety instructions prior to using this demonstration board.
This Engineering Evaluation Unit or Demonstration Board must only be used for assessing IC performance in a
laboratory setting. This product is not intended for any other use or incorporation into products for sale.
This product must only be used by qualified technicians or professionals who are trained in the safety procedures
associated with the use of demonstration boards.
Risk of Electric Shock
• The direct connection to the AC power line and the open and unprotected boards present a serious risk of electric
shock and can cause serious injury or death. Extreme caution needs to be exercised while handling this board.
• Avoid contact with the exposed conductor or terminals of components on the board. High voltage is present on
exposed conductor and it may be present on terminals of any components directly or indirectly connected to the AC
line.
• Dangerous voltages and/or currents may be internally generated and accessible at various points across the board.
• Charged capacitors store high voltage, even after the circuit has been disconnected from the AC line.
• Make sure that the power source is off before wiring any connection. Make sure that all connectors are well
connected before the power source is on.
• Follow all laboratory safety procedures established by your employer and relevant safety regulations and guidelines,
such as the ones listed under, OSHA General Industry Regulations - Subpart S and NFPA 70E.
Suitable eye protection must be worn when working with or around demonstration boards. Always
comply with your employer’s policies regarding the use of personal protective equipment.
All components and metallic parts may be extremely hot to touch when electrically active.
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1. INTRODUCTION
The CS1680 is a cascade boost-buck dimmable LED controller IC. The CS1680 uses a Cirrus Logic proprietary intelligent digital control that provides exceptional single-lamp and multi-lamp transformer compatibility for non-dimmer 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-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. Protection algorithms such as output open/short,
overcurrent detection, boost overvoltage, and overtemperature thermistors protect the system during abnormal conditions. 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 designed for an output load of 6xLEDs in series at 430mA (
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.
18V typical).
Extreme caution needs to be exercised while handling this board. This board is to be used by trained professionals
only.
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2. SCHEMATIC
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Figure 1. Schematic
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