ON Semiconductor CAT4201 Manual

CAT4201 LED Driver Evaluation Board Manual
INTRODUCTION
This document describes
evaluation board for the CAT4201 high efficiency
step-down LED driver. Boards equipped with a 9V
battery and separate LED module can be used for
demonstrations (see Figure 1).
The CAT4201 is a high efficiency step-down LED
driver from Catalyst Semiconductor. This device is
designed to drive high brightness LEDs up to 350mA
from a power supply up to 28V. The LED brightness is
controlled by a single resistor from the RSET pin to
GND. Analog dimming and idle mode control are
available through the CTRL input. An external circuit
is provided on the CAT4201EVAL2 for PWM dimming.
OPERATION PROCEDURE
The CAT4201EVAL2 board has two modes of
operation. The first is normal operation and the second
is operation with PWM dimming. Normal operation is
set by placing jumper J1 in the right side position with
pins 2 and 3 tied together. In this mode, the CTRL pin
is pulled up to the LED cathode (LED-). The LED(s) will
be at full brightness as long as the CTRL pin is greater
than 3V. LED current can be set from 70mA to 350mA
by adjusting potentiometer R2.
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11/12/2009
the CAT4201EVAL2
Figure 1. CAT4201AGEVB with LED Module
1 of 4
To set the board for PWM dimming, jumper J1 should
be placed in the left side position with pins 1 and 2
tied together. A PWM signal can be applied to the
PWM pin to dim the LED brightness. The amplitude of
the PWM signal should be greater than 1V.
DEVICE DEMONSTRATION
To set up the CAT4201EVAL2 for demonstrations, the
board should be configured for normal operation with
a 9V battery securely placed in the holder. A separate
LED module should also be plugged into the 6-pin
connector, as shown in Figure 1. To turn on the LED,
press and hold the POWER button. The LED will turn
off once the button is released.
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