WARNING: DANGER – HIGH VOLTAGES ARE PRESENT ON THIS EVALUATION BOARD AL9910EV6 ISOLATED LED DRIVER USER GUIDE Fig. 1 AL9910EV6 evaluation board connection diagram Issue 4 – June 2011 © Diodes Incorporated, 2011 www.diodes.com AL9910EV6 DESCRIPTION The AL9910EV6 is an offline isolated LED driver evaluation board designed to work on 110V AC line voltage. It provides four constant LED current outputs which drive four seperate strings of between 8 and 14 LEDs, with a LED current of 75mA per string. It will provide a total LED power ranging from 8W to 15W. AL9910EV6 SETUP AND TESTING PROCEDURE Prerequiste 1. AL9910EV6 evaluation board. 2. Four sets of LEDs strings with 8 to 14 series-connected LEDs. Please note that the number of LEDs in each string must be equal. The LEDs should be mounted on a heatsink capable of a power dissipation of 8 to 15W. 3. For safety reasons during testing, please use an isolated 110V AC source from the output of an isolation tranformer. For public demonstration, the evaluation board and LEDs should be fitted into a transparent case with sufficient insulation to meet the local safety requirements. Connections and Power up 1. 2. 3. 4. Preset the isolated AC source to either 110VAC. ENSURE THAT THE AC SOURCE IS SWITCHED OFF OR DISCONNECTED. Solder the anode wires of all LED strings to the LED+ terminal. Solder the cathode wires of the four LED strings individually to the LED1-, LED2-, LED3- and LED4terminals. Connect ammeters in series with the cathode wires if LED current measurements are required. 5. Connect the two AC line wires to the AC1 and AC2 terminals which are located at the bottom left hand corner of the evaluation board. 6. Ensure that the area around the board is clear and safe, and preferably that the board and LEDs are enclosed in a transparent safety cover. 7. Turn on the mains switch. LED string should light up. DO NOT TOUCH THE BOARD, LEDs OR BARE WIRING. Caution: The input terminals carry high voltage during operation! Issue 4 – June 2011 www.diodes.com © Diodes Incorporated 2011 2 AL9910EV6 OPERATION The AL9910A device is a PWM high-efficiency LED driver control IC. It allows efficient operation of High Brightness (HB) LEDs from voltage sources ranging from 85VAC up to 265VAC. The AL9910A can be configured to work in either fixed frequency or constant OFF-time mode. In fixed frequency mode, the AL9910A controls an external MOSFET at a fixed switching frequency up to 300kHz, which can be programmed using a single resistor. The LED string is driven at a constant current rather than at a constant voltage, thus providing constant light output and enhanced reliability. The output current can be programmed between a few milliamps and more than 1.0A. Input filter and Rectifier section In order to meet the EMI requirement, CX1, CX2, CX3, CX4, L1 and L2 are used to provide sufficient filtering for both differential-mode and common-mode noise generated from the switching converter circuit after the bridge rectifier. The rectified line voltage from the bridge rectifier DB1 is fed into a valley-filled passive power factor correction stage to provide a high power factor for the AC line input. The passive PFC stage comprises of C1, C2, D1, D2, D3 and R1. This design gives power factors of greater than 0.9. Constant Current Flyback Converter section The isolated Flyback converter section consists of LED controller AL9910A (U1), ultra-fast free-wheeling rectifier ES2G (D6), transformer (T8) and a high voltage MOSFET switch (Q1). On this evaluation board, the AL9910A is configured to operate in the constant frequency mode to provide the best LED current regulation. The switching frequency of the AL9910A is set to 100kHz using resistor R2. Please refer to the product datasheet for more details on how to configure the constant frequency mode. The Flyback converter have been designed to provide an total output current of 300mA. The LED current is regulated with an isolated secondary side feedback, consisting of an opto coupler (U2), sense resistors (R1, R2) and voltage reference (U3). The LED current level is set by resistors R1 and R2. The voltage regulator network consisting of Q2, R9 and Z2 provides stable voltage to the AL9910A from the transformer auxillary winding. Zener diode Z4 and resistor R13 provides protection to the power stage under open LED condition. Multi-channel LED Current Balancing section In this section of the evaluation board, bipolar transistors Q4-Q7 are connected as current mirror to provide an effective LED current balancing function to drive up to 4 strings of LEDs with minimal losses. The transistors are mounted as close to one another on the PCB to achieve the best possible thermal coupling. R16, R17, R22 and R23 are the transistor’s emitter resistors added to improve the LED current balancing. Issue 4 – June 2011 www.diodes.com © Diodes Incorporated 2011 3 AL9910A AL9910EV6 Fig. 2 AL9910EV6 Schematic Diagram Issue 4 – June 2011 www.diodes.com © Diodes Incorporated 2011 4 AL9910EV6 PARTS LIST Ref U1 U2 U3 Q1 Q2 Q3 Q4, Q5, Q6, Q7 D1, D2, D3 D4 D5 D6 DB1 Z1 Z2 Z3 Z4 R1 R2 R3,R4 R5 R6 R7 R8, R10 R9 R11 R13 R14 R15, R20 R16, R17, R22, R23 R18, R19, R24, R25 R21 F1 C1,C2 C4,C11 C5 C7,C8 C10 CX1,CX2, CX3, CX4 MOV1 L1 L2 T1 Description Universal high brightness LED driver Opto coupler CTR 80-160% Shunt regulator N-ch 600V MOSFET 3.2A, QG(max) = 16nC NPN Transistor 60V NPN Transistor P/N AL9910A FOD817A300 ZTLV431 Package SO8 SPB03N60S5 MMBT2222A MMBTA06 TO252 SOT23 SOT23 60V NPN Transistor FZT853 SOT223 1A 1KV diode tRR=1.8µs 400V 1A ultrafast recovery diode 150V 400mA switching diode 400V 2A ultrafast recovery diode 1A, 600V bridge rectifier 100V 1W Zener 9.1V 50mW Zener 16V 500mW Zener 56V 500mW Zener 10R 3W resistor, +/-50ppm/C, +/-1% generic 226K 0.125W +/-1% generic 0R 0.125W +/-5% generic 0R5 0.25W +/-1% generic 5K6 0.125W +/-5% generic 100K 0.125W +/-5% generic 5K1 0.125W +/-5% generic 1K 0.125W +/-5% generic 10K 0.25W +/-5% generic 20K 0.125W +/-5% generic 470R 0.125W +/-5% generic 8R2 0.33W +/-1% generic S1M-13-F MUR140 BAV20W-7 ES2G DF06S 1N4764ADO41 BZT52C9V1-7 DDZ9703 MMSZ5263B SMA DO-41 SOD123 SMB SOT23 Manufacturer Diodes Inc Fairchild Diodes Inc Infineon Diodes Inc Diodes Inc Diodes Inc Diodes Inc DO-41 SOD123 SOD123 SOD123 Diodes Inc Diodes Inc Diodes Inc Diodes Inc Diodes Inc Diodes Inc Diodes Inc Diodes Inc Wire wound 0805 0805 1206 0805 0805 0805 0805 1206 0805 0805 1206 2R2 0.25W +/-1% generic 1206 0R 0.25W +/-1% generic 1R 0.25W +/-1% generic 10R 1W fusible resistor +/-200ppm generic 33µF 450V electrolytic capacitor 4.7µF 25V X7R 1µF 50V X7R 33µF 63V 100nF 16V X7R 1206 1206 Panasonic EEUED2E330 1206 1206 0805 Panasonic 100nF 275VAC, Film, X2, 20% 275V Varistor, 21J 6.8mH 290mA 30mH 300mA common mode choke 800µH Flyback transformer turn ratio = 1.76:1 ECQU2A104ML B72207S0271K101 19R685C B82791G2301N001 OWTR-PT25C774 Issue 4 – June 2011 5mm pitch EER25 www.diodes.com © Diodes Incorporated 2011 5 Epcos Murata Epcos Olewoff AL9910EV6 PERFORMANCE Efficiency vs Input Voltage 90 . 12 LEDs 10 LEDs 8 LEDs Efficiency (%) 85 80 75 70 85 90 95 100 105 110 115 120 125 130 Input Voltage (V) . Power Factor vs Input Voltage 1.00 12 LEDs 10 LEDs 8 LEDs Power Factor 0.95 0.90 0.85 0.80 0.75 0.70 85 90 95 100 105 110 115 120 125 130 Input Voltage (V) Issue 4 – June 2011 www.diodes.com © Diodes Incorporated 2011 6 AL9910EV6 . LED Current vs Input Voltage (12 LEDs) 100.00 LED1LED2LED3LED4- LED Current (mA) 90.00 80.00 70.00 60.00 50.00 85 90 95 100 105 110 115 120 125 130 Input Voltage (V) Operating waveforms during normal operation (Orange: AL9910A’s gate output voltage; Green: Q1’s Drain current; Blue: Q1’s Drain voltage) Issue 4 – June 2011 www.diodes.com © Diodes Incorporated 2011 7 AL9910EV6 Operating waveforms during start up condition (Orange: AL9910A’s gate output voltage; Green: Q1’s Drain current; Blue: Q1’s Drain voltage) Issue 4 – June 2011 www.diodes.com © Diodes Incorporated 2011 8 AL9910EV6 INTENTIONALLY BLANK Issue 4 – June 2011 www.diodes.com © Diodes Incorporated 2011 9 AL9910EV6 INTENTIONALLY BLANK Issue 4 – June 2011 www.diodes.com © Diodes Incorporated 2011 10 AL9910EV6 INTENTIONALLY BLANK Issue 4 – June 2011 www.diodes.com © Diodes Incorporated 2011 11 AL9910EV6 IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 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