Linear LT3746 Manual

Description
Demonstration circuit 1406A features the LT
32-channel 20mA LED driver with buck controller and se-
rial interface. Each channel has an individually adjustable
12-bit (4096-step) grayscale PWM dimming control and
a 6-bit (64-step) dot correction current adjustment. Both
dimming control and current adjustment are accessible
via a 30MHz cascadable serial data interface. Individual
open/short LED and overtemperature flags are sent back
during status read-back.
Three LT3746's are connected in series to control 32 RGB
LEDs stuffed on the demo board. Each IC drives a separate
color. The evaluation software installed in a host computer
perForMAnce sUMMArY
SYMBOL PARAMETER
V Input Supply Range
IN
V Pre-Charge Voltage (Red)
OUT-R
V Pre-Charge Voltage (Green)
OUT-G
V Pre-Charge Voltage (Blue)
OUT-B
f Free-Running Switching Frequency
S
DEMO MANUAL DC1406A
32-Channel LED Driver
3746, communicates with the DC1406A via the interface board
®
DC590B, an USB serial controller.
The LT3746 data sheet gives a complete description of
the part, its operation and application information. The
datasheet must be read in conjunction with this quick start
guide for working on or modifying the demo circuit 1406A.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
QuikEval is a trademark of Linear Technology Corporation. All other trademarks are the property
of their respective owners.
Specifications are at T = 25°C.
A
CONDITIONS
LT3746
MIN TYP MAX
9 40
3.0
4.2
4.2
400
UNITS
V
V
V
V
kHz
dc1406afa
1