ZXLD1371EV1 EVALUATION BOARD USER GUIDE DESCRIPTION The ZXLD1371EV1, Figure 1, is an evaluation board for the ZXLD1371 LED driver chip. The board is in a Buck configuration with an input voltage of 48 VDC and will drive a string of 12 LEDs. It is set for an output current of 1.5A and offers convenient connections for external control inputs and monitoring. The board also includes components for reducing radiated and conducted EMI emissions. + 48V DC 12 LEDS Figure 1: ZXLD1371EV1 evaluation board and connection diagram QUICK START 1) Connect 48V 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 1.5A, 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. ZXLD1371EV1 Connection Point Definition Name Description Vin Positive supply voltage. 48V DC GND Supply Ground (0V). PWM External PWM dimming input 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 ZXLD1371EV1 L2 10uH LQH88 VIN VINDRIVER C14 C13 100nF 2u2F 100V C12 2u2F 100V C11 2u2F 100V C10 2u2F 100V C5 C6 2u2F 47uF NOT FITTED 100V 100V C7 2u2F 100V C8 2u2F 100V C9 2u2F 100V R3 R1 ISM 0R L3 LEDA C15 1.5nF 100V MPZ2012S300A 0R27 R2 C4 0R3 1uF 100V VAUX C3 1uF GND LEDK D1 PDS3100 C2 100nF 100V L1 33uH MSS1278 3 4 TADJ R4 Q1 G 13 ISM 12 VIN ADJ REF STATUS TADJ SHP FLAG S DMN6068LK3 5 14 STATUS NC NC R6 1k8 2 PGND REF 10 0R 17 0R GATE REF 8 9 R5 ADJ GI 7 1 LX D PWM SGND 16 PAD 15 6 PWM VAUX 11 LX U1 IC - ZXLD1371 C16 1.5nF 100V R7 47k C1 330pF FLAG Figure 2: ZXLD1371EV1 evaluation board Schematic ZXLD1371EV1 EVALUATION BOARD REFERENCE DESIGN The ZXLD1371EV1 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 1.5A. The board has three control inputs and multiple signal monitoring points. The PWM input allows the user to input a PWM brightness signal. It is recommended to be between 100Hz and 500Hz for maximum LED current dynamic range. 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 ZXLD1371EV1 ZXLD1371EV1 Component list QTY PCB IDENT VALUE DESCRIPTION 1 1 U1 Q1 ZXLD1371 DMN6068LK3 1 1 1 2 1 1 1 1 1 2 0 8 D1 R1 R2 R3, R5 R4 R6 R7 C1 C2 C3, C4 C5 C6, C7, C8, C9, C10, C11, C12, C13 C14 C15, C16 L1 PDS5100 0R27 0R3 0R 0R0 1k8 47k 330pF 100nF 1uF DO NOT FIT 2u2F TSSOP16EP LED driver IC – Diodes Zetex 60V N-Channel Enhancement Mode MOSFET – Diodes Inc. Freewheeling diode 5A, 100V – Diodes Inc. Resistor 1206 1% thick film 250ppm generic Resistor 1206 1% thick film 250ppm generic Resistor 0805 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 Capacitor 0805, 100v C0G generic Capacitor 0603, 100V X7R generic Capacitor 1206, 100V X7R generic Electrolytic capacitor P5D10 Capacitor, 1812, 100V X7R generic Murata GRM43ER72A225KA01L TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11 Test Point 1 2 1 11 100nF 1n5F 33uH Capacitor 0805, 100v X7R generic Capacitor 0805, 100v X7R generic Coilcraft MSS1278-333MLB NIC Components NPIS27H330MTRF 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 ZXLD1371EV1 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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