ZXLD1371EV6 User Guide Issue 1

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
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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
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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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© Diodes Incorporated 2012
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ZXLD1371EV6
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