QUICK START GUIDE FOR DEMONSTRATION CIRCUITS 1071
MAIN/CAM LED CONTROLLER
LTC3210-2/LTC3210-3
1
WARNING: The LEDs on this demo board produce very bright light. Do not look directly at LEDs when power is
applied. Serious eye damage may occur.
DESCRIPTION
Demonstration circuit 1071 is a multi-display LED
controller featuring the LTC3210-2 or the LTC3210-3.
The LTC3210-2/LTC3210-3 are low noise charge
pumps designed to drive three or four MAIN LEDs
and one high current CAM LED. The LTC3210-
2/LTC3210-3 require only four small ceramic capaci-
tors plus two resistors to form a complete LED power
supply and current controller.
The maximum display currents are set with a 30.1K
ohm resistor to provide up to 20mA for each Main
LED and a 24.3K ohm resistor to provide up to
378mA for the CAM display. Current for each LED is
controlled with a precision internal current source.
The intensity of the displays are adjusted by strobing
the ENM and ENC pins. See the LTC3210-2/LTC3210-
3 data sheet for more information on this process.
The DC1071 uses a PIC controller to interface be-
tween the DC590 board and the LTC3210-2/LTC3210-
3 via a 2-wire I
2
C serial interface. There are 32 dim-
ming states available for the MAIN display and 8
dimming states available for the CAM display.
The charge pump optimizes efficiency based on the
voltage across the LED current sources. The part
powers up in 1X mode and will automatically switch
to boost mode whenever any enabled LED current
source begins to drop out. The first dropout switches
the part to 1.5X mode and a subsequent dropout
switches the part into 2X mode. The part resets to 1X
mode whenever the part is shut down.
Design files for this circuit board are available. Call
the LTC factory.
, LTC and LT are registered trademarks of Linear Technology Corporation.
QUICK START PROCEDURE
Demonstration circuit 1071 is easy to setup. Refer
to Figure 1 for the proper measurement equipment
setup and follow the procedure below.
1.
Refer to the DC590 Quick Start guide for
QuikEval
TM
setup and software installation details.
2.
Make sure the USB cable is connected between
the computer and the DC590 controller board.
3.
Connect DC1071 to the DC590 USB Serial Con-
troller using the supplied 14-conductor ribbon
cable as shown in Figure 1.
4.
Attach a 2.9 – 4.5V power source to the Vin and
GND turrets of the DC1071 demo board. This is
the Vin power supply for the device (see applica-
tion schematic). The DC1071 has an extra 4.7uF
de-coupling capacitor between Vin and GND to
help accommodate long lead lengths. The DC590
board gets its power from the USB cable.
5.
Run the QuikEval
TM
program. The program de-
tects the DC1071 and displays the LTC3210-2/ 3
control window (shown in Figure 2).
