ZXLD1371EV3 EVALUATION BOARD USER GUIDE DESCRIPTION The ZXLD1371EV3, Figure 1, is an evaluation board for the ZXLD1371 LED driver chip. The board is in a Boost configuration with an input voltage of 12 VDC and will drive a string of 12 LEDs. It is set for an output current of 350mA and offers convenient connections for external control inputs and monitoring. The board also includes additional filters for conducted EMC requirements. + 12V DC 12 LEDS Figure 1: ZXLD1371EV3 evaluation board and connection diagram QUICK START 1) Connect 12V DC supply across Vin and GND points (observe correct polarity). 2) Connect LED string across LED A and LED K points (observe correct polarity). LED current is set at 350mA, so ensure LED string is capable of this current. 3) Cover LED string or wear eye protection. Do not look directly at LEDs in use. 4) Switch on DC power supply. ZXLD1371EV3 Connection Point Definition Name Description Vin Positive supply voltage. 12V DC GND Supply Ground (0V). തതതതതതതത External PWM dimming input (note that this input is inverted) PWM ADJ External DC dimming input (Remove R8 for DC Dimming) TADJ External thermal dimming input (NTC to GND) VAUX VAUX monitoring point FLAG FLAG pin monitoring point STATUS STATUS pin monitoring point LX LX monitoring point LED K LED Cathode connection LED A LED Anode connection Issue 1 – April 2012 © Diodes Incorporated, 2012 www.diodes.com ZXLD1371EV3 D5 S1A L2 VINF VIN 10uH C14 2u2F 100V C15 2u2F 100V C16 2u2F 100V C4 47uF DO NOT FIT 100V C5 2u2F 100V C6 2u2F 100V C7 2u2F 100V R3 R1 0R33 R2 0R DO NOT FIT GND R4 LX 100R D2 ISM 0R33 VAUX C2 1uF 100V DFLS140 D3 BZT52C51 C1 100nF LX R7 1k8 2 3 4 13 GATE R5 10 0R C11 2u2F 100V Q1 G ADJ REF STATUS TADJ SHP L3 PDS5100 FLAG C8 1uF 100V C9 1uF 100V LEDK 14 REF 8 9 7 6 17 LEDA 10uH S DMN6068LK3 PWM R10 62k C10 2u2F 100V 5 NC NC R9 180k REF LX D1 LX D GI PGND 0R ISM 11 R6 10k 1 R8 U1 IC - ZXLD1371 PWM SGND G PWM 16 PAD 15 GI D Q3 2N7002 S VIN VAUX PWM 12 L1 68uH MSS1278 R12 47k C3 330pF Q2 D STATUS 2N7002 FLAG D4 BZT52C51 G S R11 2k ADJ TADJ Figure 2: ZXLD1371EV3 evaluation board Schematic ZXLD1371EV3 EVALUATION BOARD REFERENCE DESIGN The ZXLD1371EV3 is a Boost reference design, based around the ZXLD1371 lighting IC. The circuit will accept an input voltage of 12 VDC and can drive an output string of 12 LEDs at 350mA. The board has three control inputs and multiple signal monitoring points. തതതതതതതത input allows the user to input a PWM brightness signal. It is recommended to be The PWM between 100Hz and 500Hz for maximum LED current dynamic range. Note that the PCB includes a circuit that inverts the signal fed onto this input, in order that the input can be wire-ORed with the overvoltage protection circuit. The ADJ input allows for DC dimming input, with a voltage between 0.125V and 1.25V for full brightness. In order to use an external control on ADJ, R8 must be removed. The TADJ input is for connection of an external 10k NTC thermistor which will dim the LEDs as temperature increases, for maximizing LED lifetime. With a 10k NTC and R7 = 1.8kΩ, the thermal trip point will be around 70ºC. The VAUX monitoring point allows easy connection to the chip auxiliary power supply and measurement of the bootstrap circuit where used. It can also be used to feed in an external source of VAUX if R3 and R4 are removed. R4 connects VAUX to LX through D2 as a bootstrap circuit, allowing for operation at low Vin values (5-8V). If bootstrapping is not required, remove R4 and fit R3 = 0Ω. FLAG and STATUS monitoring points allow these outputs of the chip to be monitored. For further information on output information on these pins see the ZXLD1371 datasheet. The LX switching point can be monitored on the test point, in order to easily monitor the output PWM. The LED string load can be connected across the LED A and LED K points. Issue 1 – April 2012 www.diodes.com © Diodes Incorporated 2012 2 ZXLD1371EV3 ZXLD1371EV3 Component list QTY PCB IDENT VALUE DESCRIPTION 1 1 U1 Q1 ZXLD1371 DMN6068LK3 2 1 1 2 1 2 0 1 1 1 1 1 1 1 1 1 1 3 1 0 8 Q2, Q3 D1 D2 D3, D4 D5 R1, R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 C1 C2, C8, C9 C3 C4 C5, C6, C7, C10, C11, C14, C15, C16 L1 2N7002 PDS5100 DFLS140 BZT52C51 S1A 0R27 DO NOT FIT 100R 0R0 10k 1k8 0R 91k 24k 2k 47k 100nF 1uF 330pF DO NOT FIT 2u2F TSSOP16EP LED driver IC – Diodes Zetex 60V N-Channel Enhancement Mode MOSFET – Diodes Inc. SOT23 FET - Diodes Zetex Freewheeling diode 5A, 100V – Diodes Inc. Schottky diode 1A, 40V – Diodes Inc. Zener, 51V 400mW SOD123 – Diodes Inc. Diode, 1A SMA – Diodes Inc Resistor 1206 1% thick film 250ppm generic Resistor 0805 Resistor 1206 1% thick film 250ppm generic Resistor 1206 1% thick film 250ppm generic Resistor 0805 1% thick film 250ppm generic Resistor 0805 1% thick film 250ppm generic Resistor 0805 1% thick film 250ppm generic Resistor 0805 1% thick film 250ppm generic Resistor 0805 1% thick film 250ppm generic Resistor 0805 1% thick film 250ppm generic Resistor 0805 1% thick film 250ppm generic Capacitor 0603, 100V X7R generic Capacitor 1206, 100V X7R generic Capacitor 0805, 100v C0G generic Electrolytic capacitor P5D10 Capacitor, 1812, 100V X7R generic Murata GRM43ER72A225KA01L L2, L3 TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11 10uH Test Point 1 2 11 68uH Coilcraft MSS1278-683MLB NIC Components NPIS27H680MTRF Murata LQH88PN100M38L 2.15mm dia. test loops, green, generic, Hughes 100-108 Note: The component values and part numbers are correct at the time of publication. Diodes Inc. reserves the right to substitute other parts where necessary, without further notification. Issue 1 – April 2012 www.diodes.com © Diodes Incorporated 2012 3 ZXLD1371EV3 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. Diodes Incorporated does not assume any liability arising out of the application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or trademark rights, nor the rights of others. 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