QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 914
MAIN/CAM LED CONTROLLER
LTC3210
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 914 is a multi-display LED con-
troller featuring the LTC3210.
The LTC3210 is a low noise charge pump designed to
drive four MAIN LEDs and one high current CAM
LED. The LTC3210 requires only four small ceramic
capacitors 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 for the Main display and a 24.3K ohm
resistor 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 data sheet
for more information on this process. The DC914
uses a PIC controller to interface between the DC590
board and the LTC3210 via a 2-wire I
2
C serial inter-
face. There are 8 dimming states available for the
MAIN and CAM displays.
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 914 is easy to setup. Refer to
Figure 1 for 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 DC914 to the DC590 USB Serial Control-
ler 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 DC914 demo board. This is
the Vin power supply for the LTC3210 (see appli-
cation schematic). The DC914 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 DC914 and displays the LTC3210 con-
trol window (shown in Figure 2).
