G
N
D
T
X
PW
M
1
G
N
D
T
X
PW
M
1
G
N
D
ST
R
O
BE
PW
M
2
G
N
D
ST
R
O
BE
PW
M
2
Setup
Figure 2. VIO Jumper Settings
J3 - LEDB CON - is the jumper used to connect the on-board backlight LEDs to the LED output of the
driver.
J20 and J21 - D1B and D2B LEDs - are the jumper used to select the number of LEDs in each backlight
string.
J11 and J12 - D1F CON and D2F CON- are the jumpers used to connect the on-board flash LEDs to the
LED output of the driver.
J27 - STROBE - This pin provides an external method for initiating a flash event. The STROBE pin is
connected to ground via a 300 k
Ω
resistor internal to the LM3639A. To externally drive this pin, either
connect a control signal directly to the STROBE pin of the connector or place a jumper between connector
pins STROBE and PWM0. Pin PWM2 can be configured as time-adjustable voltage pulse via the General
User Interface software provided.
Figure 3. STROBE Jumper Settings
J25 - TX - This pin is used to initiate a TX-interrupt event. The TX pin is connected to ground via a 300 k
Ω
resistor internal to the LM3639A. To externally drive this pin, either connect a control signal directly to the
TX pin of the connector or place a jumper between connector pins TX and PWM1. Pin PWM1 can be
configured as continuous voltage pulses via the General User Interface software provided.
Figure 4. TX Jumper Settings
J22 - PWM- This pin provides an external method for adjusting the backlight LED brightness. The PWM
pin is connected to ground via a 300 k
Ω
resistor internal to the LM3639A. To externally drive this pin,
either connect a control signal directly to the PWM pin of the connector or place a jumper between
connector pins PWM and PWM0. Pin PWM0 can be configured to provide a continuous stream of voltage
pulses of adjustable frequency and duty cycle via the General User Interface software provided.
3
SNVU211 – March 2013
LM3639AYFQEVM User's Guide
Copyright © 2013, Texas Instruments Incorporated
