ZXLD1371EV6 EVALUATION BOARD USER GUIDE DESCRIPTION The ZXLD1371EV6, 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. + 12V DC 12 LEDS Figure 1: ZXLD1371EV6 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. ZXLD1371EV6 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 – February 2012 © Diodes Incorporated, 2012 www.diodes.com ZXLD1371EV6 LED K VIN GND C6 2u2F 100V GND C7 2u2F 100V GND R3 0R27 R2 0R DO NOT FIT GND GND VAUX LX 100R C2 1uF 100V DFLS140 D3 BZT52C51 C1 100nF R6 10k 1 R8 0R R9 91k REF 2 3 R7 1k8 4 U1 IC - ZXLD1371 LX D1 D GI GATE R5 10 0R Q1 G ADJ REF STATUS TADJ SHP LEDA LX PDS5100 PWM FLAG SGND G PWM 16 PAD 15 GI VIN 11 GND VAUX PWM LX L1 68uH MSS1278 12 GND D Q3 2N7002 S C8 1uF 100V ISM 0R27 D2 R4 GND R1 13 GND C5 2u2F 100V ISM GND C12 2u2F 100V NC NC 47uF DO NOT FIT 100V PGND C4 GND C11 2u2F 100V 5 GND REF PWM 8 9 7 6 17 R10 24k GND 14 GND GND C10 2u2F 100V S DMN6068LK3 R12 47k C3 330pF Q2 D STATUS 2N7002 FLAG D4 BZT52C51 G S R11 2k ADJ GND GND GND GND TADJ Figure 2: ZXLD1371EV6 evaluation board Schematic ZXLD1371EV6 EVALUATION BOARD REFERENCE DESIGN The ZXLD1371EV6 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. The തതതതതതതത 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. 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 – February 2012 www.diodes.com © Diodes Incorporated 2012 2 ZXLD1371EV6 ZXLD1371EV6 Component list QTY PCB IDENT VALUE DESCRIPTION 1 1 U1 Q1 ZXLD1371 DMN6068LK3 2 1 1 2 2 0 1 1 1 1 1 1 1 1 1 1 2 1 0 6 Q2, Q3 D1 D2 D3, D4 R1, R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 C1 C2, C8 C3 C4 C5, C6, C7, C10, C11, C12 L1 2N7002 PDS5100 DFLS140 BZT52C51 0R27 DO NOT FIT 100R 0R0 10k 1k8 0R 91k 24k 2k 47k 100nF 1uF 330pF DO NOT FIT 2u2F TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11 Test Point 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. 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 Coilcraft MSS1278-683MLB NIC Components NPIS27H680MTRF 2.15mm dia. test loops, green, generic, Hughes 100-108 1 11 68uH 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. 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