DLD101EV1 USER GUIDE Description The board is intended for the evaluation of Jumpers 1, 2 and 3 on the evaluation board DLD101, a linear mode constant current LED set the value of the LED current. Jumper 1 sets the LED current to 260mA, jumper 2 driver. sets it to 45mA and jumper 3 sets it to 20mA. When an input voltage higher than the forward voltage of the LED string (max. 50V) The board also incorporates a PWM input is applied to the board, the board supplies a operating between 0V and 5-10V, which can fixed current to the LED string connected to be used for PWM dimming of the LED string. its output. Ordering Information ORDER NUMBER DLD101EV1 Please note evaluation boards are subject to availability and qualified leads JP1 = 260mA JP2 = 45mA JP3 = 20mA Figure 1. DLD101 evaluation board Issue 1 – August 2011 © Diodes Incorporated, 2011 in figures www.diodes.com DLD101EV1 Quick Start Guide Required Test Equipment 12V 2A adjustable power supply, digital multimeter and high brightness LEDs Constant Current LED Driving Operation 1. Set the power supply to 8V for a string of 2 LEDs. 2. Set the current limit to 350mA. 3. Connect up the DLD101EV1 to the equipment as in Figure 1 above. 4. Set DMM1 to measure the LED current. 5. Set jumper to JP1 position. (Only one jumper should be fitted at any time). 6. Switch on the power supply and check that the LED lights up. 7. Check that the current measured on DMM1 is 260mA +/- 10mA. 8. Switch off the power supply and set jumper to JP2 position. 9. Switch on the power supply and check that the LED lights up. 10. Check that the current measured on DMM1 is 45mA +/- 5mA. 11. Switch off the power supply and set jumper to JP3 position. 12. Switch on the power supply and check that the LED lights up. 13. Check that the current measured on DMM1 is 20mA +/- 5mA. DLD101EV1 Schematic Anode VCC Vin LED A R1 82K CATHODE 1 U1 D1 2 G1 3 NC C1 4 LED K DLD101 B1 B1' S2 8 7 Q1 2N7002 PWM 6 R6 PWM 10K 5 E1 =Value SL1 1nF C1 SL2 R7 1M 1 2 1 2 1 2 JP1 JP2 JP3 R2 3R GND GND Figure 2. PCB Schematic diagram Issue 1 – August 2011 www.diodes.com © Diodes Incorporated, 2011 in figures 2 R3 3R9 R4 11R5 R5 28R DLD101EV1 Parts List Designator U1 Q1 C1 R1 R2 R3 R4 R5 R6 R7 Description Linear mode constant sink LED driver Package DFN3030D-8 Small signal MOSFET Do not fit Resistor, 82K +/- 1% 250ppm 125mW Resistor, 3R +/- 1% 250ppm 250mW Resistor, 3R9 +/- 1% 250ppm 250mW Resistor, 11R5 +/- 0.1% 250ppm 125mW Resistor, 28R +/- 1% 250ppm 125mW Resistor, 10K0 +/- 1% 250ppm 125mW Resistor, 1M0 +/- 1% 250ppm 125mW Part Number DLD101 SOT-23 2N7002 Manufacturer Diodes Inc Diodes Inc 0805 1206 1206 0805 0805 0805 0805 generic generic generic generic generic generic generic Table 1. Parts list Performance Current out (A) The performance of the DLD101 when used to regulate LED current is shown in Figure 3. With only jumper 1 fitted, a load of 2 LEDs, and a supply of 8VDC, the LED current is around 300mA at 25°C PCB and LED temperature. Over the typical lighting board temperature range, the LED current changes from 380mA at 0°C PCB temperature to 220mA at 85°C. 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0 20 40 60 80 100 Temp (C) Figure 3. LED current vs. PCB board temperature PWM dimming functionality can be implemented by applying a signal between 0V and 5-10V on the ‘PWM’ terminal. Figures 4, 5 and 6 show the LED current variation as the duty cycle of a 400Hz signal changes. Issue 1 – August 2011 www.diodes.com © Diodes Incorporated, 2011 in figures 3 DLD101EV1 300 Output Current (mA) 250 200 150 100 50 0 0 20 40 60 80 100 Duty Cycle (%) Figure 4. Duty Cycle vs. output Current for JP1 Configuration (260mA) at 400Hz 50 Output Current (mA) 40 30 20 10 0 0 20 40 60 80 100 -10 Duty Cycle (%) Figure 5. Duty Cycle vs. Output Current for JP2 Configuration (45mA) at 400Hz Issue 1 – August 2011 www.diodes.com © Diodes Incorporated, 2011 in figures 4 DLD101EV1 20 Output Current (mA) 15 10 5 0 0 20 40 60 80 100 -5 Duty Cycle (%) Figure 6. Duty Cycle vs. Output Current for JP3 Configuration (20mA) at 400Hz PCB Copper Layout & Silk Screen –Top Figure 7. PCB layout The bottom layer is a solid plane connected to LED K Issue 1 – August 2011 www.diodes.com © Diodes Incorporated, 2011 in figures 5 DLD101EV1 INTENTIONALLY BLANK Issue 1 – August 2011 www.diodes.com © Diodes Incorporated, 2011 in figures 6 DLD101EV1 INTENTIONALLY BLANK Issue 1 – August 2011 www.diodes.com © Diodes Incorporated, 2011 in figures 7 DLD101EV1 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). Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. 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