AN11136
SSL2109T/AT/SSL2129AT controller for SSL applications
Rev. 1.2 — 1 September 2014
Application note
Document information
Info
Keywords
Abstract
Content
SSL2109T/AT, SSL2129AT, buck converter, GreenChip, Down converter,
LED controller, Topology, Retrofit SSL, LED, BCM, External switch
This document describes how to design a buck converter in a low-ripple
configuration, using the SSL2109T/AT or SSL2129AT IC, with an external
MOSFET. Specifically, selecting the MOSFET and implementing it is
described.
NXP Semiconductors
AN11136
SSL2109T/AT/SSL2129AT controller for SSL applications
Revision history
Rev
v.1.2
Date
20140901
Description
revised issue
Modifications:
v.1.1
v.1
20121024
20120510
•
Equation 13
has been updated.
revised issue
first issue
Contact information
For more information, please visit:
http://www.nxp.com
For sales office addresses, please send an email to:
salesaddresses@nxp.com
AN11136
All information provided in this document is subject to legal disclaimers.
© NXP Semiconductors N.V. 2014. All rights reserved.
Application note
Rev. 1.2 — 1 September 2014
2 of 22
NXP Semiconductors
AN11136
SSL2109T/AT/SSL2129AT controller for SSL applications
1. Introduction
This application note discusses the specific external MOSFET design considerations for
the SSL2109T/AT and the SSL2129AT.
The SSL2109T/AT and SSL2129AT platforms are specifically defined to address the
market of retrofit SSL applications. It provides a controller, with an external high-voltage
switch. The devices are optimized to make cost-effective, highly efficient buck converter
solutions for high-voltage LED strings or LED modules. The buck converter is one of the
most used Switch Mode Power Supply (SMPS) topologies.
The application note
“Buck converter for SSL applications” (AN10876)
provides general
information about buck converter applications. The application note
“SSL21081/SSL21083/SSL2109 non-dimmable buck converter in low ripple configuration”
(AN11041)
describes a step-by-step design procedure for non-mains dimmable
applications.
Information and design tools for this IC can be found on the product page on the NXP web
site.
1.1 Functional description
The SSL2109A/AT and the SSL2129AT are Multi-Chip Module (MCM) SO8 packages.
They can handle up to 600 V (DC) at pins HV and DRAIN. The main features for all
variants are as follows (See
Figure 1
and
Figure 2):
Switch-mode buck controller with power-efficient boundary conduction mode of operation
with:
•
•
•
•
No reverse recovery losses in freewheel diode
Zero Current Switching (ZCS) for switch-on of switch
Zero voltage or valley switching for switch-on of switch
Smallest possible inductance value and size
High Power Factor (> 0.9), depending on application
•
Mains phase-cut dimmable using external components (SSL2109AT)
Fast transient response through cycle-by-cycle current control thus preventing:
•
Overshoots and undershoots of the LED current
Internal protections:
•
•
•
•
•
•
•
AN11136
Undervoltage LockOut (UVLO)
Leading-Edge Blanking (LEB)
OverCurrent Protection (OCP)
Short-Winding Protection (SWP; SSL2109T only)
Internal overtemperature
Brownout protection
Output short protection
All information provided in this document is subject to legal disclaimers.
© NXP Semiconductors N.V. 2014. All rights reserved.
Application note
Rev. 1.2 — 1 September 2014
3 of 22
NXP Semiconductors
AN11136
SSL2109T/AT/SSL2129AT controller for SSL applications
•
External temperature protection with single Negative Temperature Coefficient (NTC)
only
See the
SSL2109_SER and SSL2129 data sheets
(Ref.
3, Ref. 4)
for more information.
Fig 1.
Block diagram SSL2109T
AN11136
All information provided in this document is subject to legal disclaimers.
© NXP Semiconductors N.V. 2014. All rights reserved.
Application note
Rev. 1.2 — 1 September 2014
4 of 22