AN24 Datasheet, PDF (1/9 Pages) Copal Electronics – W-6237EVAL2 EVALUATION BOARD FOR W-6237

APPLICATION NOTE AN24
W-6237EVAL2 EVALUATION BOARD FOR W-6237
HIGH VOLTAGE WHITE LED DRIVER
Denisa Stefan, Applications Engineer
INTRODUCTION
This document describes the W-6237EVAL2 Evaluation Board for the COPAL ELECTRONICS W-6237 white LED
driver. The functionality and major parameters of the W-6237 can be evaluated with the W-6237EVAL2 board.
The W-6237 is a high voltage CMOS constant-current DC/DC converter that has been designed to drive with high
efficiency white or other high brightness LEDs. The high-voltage output stage allows driving up to 10 white LEDs in
series. A single external resistor sets the LED current between 5mA and 40 mA. LED current can be adjusted using
either a pulse width modulated (PWM) signal or a DC voltage. Detailed descriptions and electrical characteristics are
in the W-6237 data sheet.
W-6237EVAL2 BOARD HARDWARE
The evaluation board contains a W-6237 DC-DC boost converter and an array of white LEDs. As configured, the
board circuit is set to drive up to 8 white LEDs in series. The user can chose to connect the W-6237 output to the
LEDs string available on board or to an external LEDs string from an application.
The board provides also the option to connect a different number of LEDs available on board, 6, 7 or 8, using a jumper
shunt for one of the J2 to J4 connectors. The board schematic is shown in Figure 1.
T1
VIN
T2
GND
GND
T3
GEN/DC
J1
1
T4
GND
T5 ^GND
FB
T6
SGND
GND
SW
LQ1 ^T9 D1
C1
4,7+F
GND
R5 10K
R4
200K
GND
33+H
5
1
VIN
SW
4 ^SHDN _FB 3
GND
W-6237 ^{2 U1}
GND
C2
0,22+F
GND
R3
LED
T10
1K
100 ohm
R2
R1
6,81 ohm
GND
VOUT
T7
T8
GND
GND
L1
L2
L3
L4
L5
L6
J2
L7
J3
L8
J4
Figure 1. W-6237EVAL2 Board Schematic
© 2005 by NIDEC COPAL ELECTRONICS CORP.
Characteristics subject to change without notice
1
Document No. 6041, Rev. B