DN05013/D Design Note – DN05013/D Simple ENERGY STAR® Compliant LED Driver Retrofit in a T5 Tube using 160mA CCR Device NSI45090JDT4G Application T5 23” Fluorescent Replacement LEDs Input Voltage Power Topology I/O Isolation 110V AC ±10% 11.2W Linear NONE Figure 1 – CCR with 42 LEDs and a Bridge Rectifier Circuit Overview Key Features The objective is to build a LED retrofit using a T5 fluorescent tube fixture. A constant current regulator, NSI45090JDT4G, is incorporated, and the whole circuit exceeds ENERGY STAR® power factor rating greater than 0.7. The circuit (Figure 1) consists of a bridge rectifier using MURA160T3-D, a constant current regulator (CCR), an adjusting resistor, LEDs (Xlamp ML-E®), and GE® T5 23” fixture (Figure 2). At the input, an overload fuse can be added to protect the circuit from current spikes. Simple design AC application of LEDs No leakage or drive current 6 parts on small driver board Higher Efficiency than fluorescent Current regulation to protect LEDs Better lumen output then fluorescent Pf exceeds Energy Star Requirements The design consists of two circuit boards, one for the CCR (90mmX18mm) as in Figure 3, and one for the LED’s (516mmX18mm) as in Figure 4. The CCR board has 6 parts on it, 4 bridge diodes MURA160T3-D, 1 CCR NSI45090JDT4G, and 1 resistor of 2.5Ω. The LED board has 42 LEDs, 4 resistors of 1Ω, 4 Tyco pins, and a (250mA/125V) fuse. July 2011, Rev. 0 Circuit Operation The circuit operates as follows; the bridge rectifier consists of 4 diodes that rectify the input voltage to peak positive voltage at 155.56V @120Hz. Following in the circuit is the CCR that uses a 2.5Ω resistor to achieve 160mA of peak current regulation. Now the current flows through the two 1Ω resistors and through the LEDs. The resistors were designed in the LED board in case a voltage reduction is needed to compensate for lower Vf LEDs. They have no purpose in the circuit as is. www.onsemi.com 1 DN05013/D subtracting the CCR voltage and the 2 diode forward voltages from the total rectified input voltage. The efficiency is determined using the following equation; Build Once the fixture was purchased, the bottom side was cut open, and the internal ballast for the fluorescent tube was removed. The CCR board was installed to internally replace the existing board. The LED board was fitted to replace the fluorescent tube, 21” long and 18mm wide, and was designed to be covered by the reflector plastic cover. η= VLED × I LED (Vin − VCCR ) × I LED = Vin × I in Vin × I in Conclusions Data Analysis Figure 5 shows data captures from the oscilloscope, and demonstrates the input voltage and current relative to the rectified current through the CCR, and the CCR voltage drop. The LED voltage is simply the result of The design features better luminosity than the fluorescent, i.e. better power per light output, high power factor and low THD. The average LED light output is twice as much as that of the fluorescent while consuming about the same energy. Images Figure 2 – T5 21” Fluorescent Tube and LED Tube Figure 3 – CCR Board Used in Fixture Figure 4 – LED Board Replaces Fluorescent Tube July 2011, Rev. 0 www.onsemi.com 2 DN05013/D Capture Figure 5 – Oscilloscope Voltages and Currents Data Summary Table Fixture Vin rms Type (V)1 100.1 Cree LED Xlamp 110.2 ML-E 120.1 100.1 Slim Line Fluorescent 110.1 Tube GE 120.2 Iin rms (mA)1 78.5 115.6 132.3 182.2 189.8 200.3 P (W)1 Pf1 6.3 11.1 14.3 9.7 11.5 13.2 0.79 0.87 0.90 0.54 0.55 0.55 THD (%,A)1 76 55 47 111 111 113 Klux2 Average 3.4 5.2 5.9 2.2 2.7 2.9 CCR Temp (°C)3 50 60 80 N/A N/A N/A LED Temp (°C)3 50 60 65 N/A N/A N/A 1. Yokogawa WT210 Digital Power Meter was used under equivalent conditions for test acquisition. 2. Extech HD450 was used under equivalent conditions as reference between light sources. 3. Flir InfraCAM was used under equivalent conditions as reference between heat sources. 4. Data may vary depending on NSI45090JDT4G ±10% and Xlamp ML-E. July 2011, Rev. 0 www.onsemi.com 3 DN05013/D Additional Data PF ENERGY STAR® (Yes/No) Efficiency Inrush Limiting / Fuse Operating Temperature NSI45090JDT4G Ireg SS Yes > 0.7 89.66% @ 110V RMS AC Yes -20°C to +45°C 153mA @7.5V Bill of Materials 06/20/2011 Quantity Description Value Tolerance Footprint Manufacturer Manufacturer Part Number 1 Fuse 250mA/125V N/A SMD N/A N/A 1 CCR 45V, 90mA ±15% D-pak ON Semiconductor NSI45090JDT4G 4 Diode 600V, 1A N/A SMA ON Semiconductor MURA160T3-D 1 Resistor 2.5Ω, 1210 1% 1210 N/A Generic 1 CCR Board 2OZ Cu, 2 layers, FR-4 N/A PCB DS Electronics N/A 42 LED 3.2V, 150mA N/A 3.50X3.45mm CREE Xlamp ML-E 4 Tyco pins 0.062” diam. N/A N/A Tyco Electronics 1-66103-6 type III 4 Resistor 1Ω, 1206 1% 1206 N/A Generic 1 LED Board 2OZ Cu, 2 layers, FR-4 N/A PCB DS Electronics N/A 1 © 2011 ON Semiconductor. Disclaimer: ON Semiconductor is providing this design note “AS IS” and does not assume any liability arising from its use; nor does ON Semiconductor convey any license to its or any third party’s intellectual property rights. This document is provided only to assist customers in evaluation of the referenced circuit implementation and the recipient assumes all liability and risk associated with its use, including, but not limited to, compliance with all regulatory standards. ON Semiconductor may change any of its products at any time, without notice. Design note created by Yohai Kalderon, e-mail: [email protected] July 2011, Rev. 0 www.onsemi.com 4