Application Note 32

1

Doc. No. 6050 Rev. A

Characteristics subject to change without notice

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.

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.

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 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.

Figure 1. W-6238EVAL1 Board Schematic

S1

J1

T1

T2

T3

T4

T5

T6

GND

GND

FB

SGND

GEN/DC

LQ1

10k

200k

1k

100

R5

R4

R3

R2

6.81

R1

C1

4.7µF

C2

D1

LED

J2

J3

J4

T7

T8

GND

L1

L2

L3

L4

L5

L6

L7

L8

L9

L10

T10

T9

SW

SW

VIN

5

4

3

2

W-6238

1

FB

GND

U1

0.22µF

47µH

SHDN