MPS EV0035 User manual

EV0035
6 White LEDs, 20mA Precision
WLED Driver Evaluation Board
EV0035 Rev. 1.2 www.MonolithicPower.com 1
3/30/2006 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2006 MPS. All Rights Reserved.
The Future of Analog IC Technology
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DESCRIPTION
The EV0035 is the evaluation board for the
MP1523, which is designed for driving up to six
(6) series WLEDs from a single cell Lithium Ion
battery. The board is set up to obtain 20mA
LED current. The current can be adjusted by
varying the resistor R2.
The MP1523 uses current limited, variable
frequency architecture to regulate the LED
current while maintaining high efficiency. The
BIAS pin measures the output voltage and turns
off the converter if an over voltage condition is
present to prevent damage due to an open
circuit condition. The LED current is measured
with an external current sense resistor. The low
0.4V full-scale regulation threshold and 0.5Ω
power switch minimize power loss to improve
efficiency.
ELECTRICAL SPECIFICATIONS
Parameter Symbol Value Units
Input Voltage VIN 2.7 – 25 V
# of WLEDs up to 6
LED Current ILED 20 mA
FEATURES
•2.7V to 25V Input Voltage Range
•Drives up to 6 Series White LEDs
•Surface-Mount Components
•Fully Assembled and Tested
APPLICATIONS
•Cell Phones
•Handheld Computers and PDAs
•Digital Still and Video Cameras
•Small LCD Displays
“MPS” and “The Future of Analog IC Technology” are Trademarks of Monolithic
Power Systems, Inc.
EV0035 EVALUATION BOARD
(L x W x H) 2.0” x 1.4” x 0.5”
(5.0cm x 3.5 x 1.2cm)
Board Number MPS IC Number
EV0035 MP1523DT
85
80
75
70
EFFICIENCY (%)
2.5 3.0 3.5 4.0 4.5
V
IN
(V)
EV0035_AC01
Efficiency vs VIN

EV0035 – 6 WHITE LEDs, 20mA PRECISION WLED DRIVER EVALUATION BOARD
EV0035 Rev. 1.2 www.MonolithicPower.com 2
3/30/2006 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2006 MPS. All Rights Reserved.
TM
EVALUATION BOARD SCHEMATIC
EV0035_S01
MP1523
U1
EN
GND
1
5
3
4
2
SW
BIAS
FB
LED1
LED2
LED3
LED4
LED5
LED6
D1
MBR0540
VCC
GND
EN
J1
GND C3
10nF
EV0035 BILL OF MATERIALS
Qty Ref Value Description Package Manufacturer Part Number
2 C1, C2 1µF Ceramic Cap., 50V, X7R 1206 TDK C3216X7R1H105K
1 C3 10nF Ceramic Cap., 50V, X7R 0603 TDK C1608X7R1H103K
1 D1 Diode Schottky, 40V, 500mA SOD-123 ON
Semiconductor MBR0540T1
6 LED1 to
LED6 Not Stuffed
1 L1 15µH Inductor, 450mA SMD Sumida CDRH3D16-150NC
1 R1 100kΩFilm Res., 5% 0603 Panasonic ERJ-3GEYJ104V
1 R2 20ΩFilm Res., 5% 0603 Panasonic ERJ-3GEYJ200V
1 U1 White LED Driver SOT23-5 MPS MP1523DT

EV0035 – 6 WHITE LEDs, 20mA PRECISION WLED DRIVER EVALUATION BOARD
EV0035 Rev. 1.2 www.MonolithicPower.com 3
3/30/2006 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2006 MPS. All Rights Reserved.
TM
PRINTED CIRCUIT BOARD LAYOUT
Figure 1—Top Silk Layer Figure 2—Top Layer
Figure 3—Bottom Layer

EV0035 – 6 WHITE LEDs, 20mA PRECISION WLED DRIVER EVALUATION BOARD
NOTICE: The information in this document is subject to change without notice. Please contact MPS for current specifications.
Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS
products into any application. MPS will not assume any legal responsibility for any said applications.
EV0035 Rev. 1.2 www.MonolithicPower.com 4
3/30/2006 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2006 MPS. All Rights Reserved.
TM
QUICK START GUIDE
1. Solder LED1 – LED6 onto the board.
2. Connect VCC to the power source’s positive output.
3. Connect GND to supply ground.
4. Remove the jumper J1 to allow the MP1523 to automatically start when power is applied. Place the
shorting clip across J1 to disable the MP1523. A logic signal may be applied to EN to
enable/disable the MP1523, provided the shorting clip is not installed across J1.
5. To dim the LEDs, remove the shorting clip from J1 and apply a PWM signal to the EN pin. Adjusting
the duty cycle of the PWM signal determines the brightness of the LEDs.