AN26 Datasheet, PDF (1/8 Pages) Copal Electronics – W-6137EVAL1 EVALUATION BOARD FOR W-6137

APPLICATION NOTE AN26
W-6137EVAL1 EVALUATION BOARD FOR W-6137
WHITE LED DRIVER
Denisa Stefan, Applications Engineer
INTRODUCTION
This document describes the W-6137EVAL1 Evaluation Board for the COPAL ELECTRONICS W-6137 white LED
driver. The functionality and major parameters of the W-6137 can be evaluated with the W-6137EVAL1 board.
The W-6137 is a CMOS constant-current DC/DC converter that has been designed to drive with high efficiency white or
other high brightness LEDs. The device drives up to 5 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-6137 data sheet.
W-6137EVAL1 BOARD HARDWARE
The evaluation board contains a W-6137 DC-DC boost converter and an array of white LEDs. As configured, the board
circuit is set to drive up to 5 white LEDs in series. The user can chose to connect the W-6137 output to the on board
LEDs string or to an external LEDs string from an application. The boards are populated with 3 white LEDs in series
connected to the W-6137 output by J3 jumper shunt connector.
The board layout provides also the option to connect a different number of LEDs, 2, 4 or 5, using a jumper shunt for one of
the J2, J4 or J5 connectors. The board schematic is shown in Figure 1.
W-6137
Figure 1. W-6137EVAL1 Board Schematic
The board is powered from an external voltage applied to the VIN (T1) pad or optional from an attached 3V battery (2 x
1.5V AA). The circuit is delivered with the jumper shunt on the J3 connector, which connects the 3 LEDs string available
on board to the W-6137 output.
© 2005 by NIDEC COPAL ELECTRONICS CORP.
Characteristics subject to change without notice
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Document No. 6043, Rev. A