AN32 Datasheet, PDF (1/7 Pages) Copal Electronics – 10-LED Boost Converter

Application Note 32
W-6238EVAL1 Evaluation Board for W-6238
10-LED Boost Converter
Denisa Stefan, Applications Engineer
1. INTRODUCTION
This document describes the W-6238EVAL1
Evaluation Board for the COPAL ELECTRONICS
W-6238 High Efficiency 10-LED Boost Converter.
The functionality and major parameters of the
W-6238 can be evaluated with the W-6238EVAL1
board.
2. W-6238EVAL1 BOARD HARDWARE
The evaluation board contains a W-6238 DC-DC
boost converter in a typical application circuit. As
configured, the board circuit is set to drive up to 10
white LEDs in series. The user can chose to connect
the W-6238 output to the on-board LEDs string or to
an external LEDs string from an application.
The W-6238 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 characte-
ristics are in the W-6238 data sheet.
The board provides the option to connect a different
number of LEDs available on board, 8, 9 or 10, using
a jumper shunt for one of the J2 to J4 connectors. The
board schematic is shown in Figure 1.
SW
T1
LQ1
T9
D1
V_IN
S1
C1
47µH
C2
T2
4.7µF
5
1
0.22µF
GND
T3
GEN/DC
T4
GND
J1
R4
200kŸ
R5 10kŸ
VIN
SW
W-6238
4
SHDN
3
FB
GND
2 _U1
R3
1kŸ _R2
100Ÿ
R1
T5
FB
6.81Ÿ
LED
T10
V_OUT
T8
GND
T7
L1
L2
L3
L4
L5
L6
L7
T6
SGND
J2
L8
J3
L9
L10
J4
Figure 1. W-6238EVAL1 Board Schematic
© 2006 NIDEC COPAL ELECTRONICS CORP.
1
Characteristics subject to change without notice
Doc. No. 6050 Rev. A