T6319A Taiwan Memory Technology, T6319A Datasheet - Page 6

• Manufacturer Part Number: T6319A
• Description: High Efficiency 2X charge Pump
• Manufacturer: Taiwan Memory Technology

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White LED Backlight Driver
LED Selection:
In applications where the T6319A is utilized as a white LED backlight driver, LEDs with forward
voltages up to 5.5V may be used. The T6319A is available in 8 regulated output voltage versions:
2.5V ~ 5.5V. The output voltage option selected will determine the maximum LED forward voltage
that can be driven. The trade-off for the lower 4.5V output voltage version is the device’s ability to
supply greater output current. Refer to the “Output Voltage vs. Output Current" curves in the
Typical Characteristics section of this datasheet to determine the best T6319A output voltage option
based on the requirements of given application.
LED Ballast Resistors:
To set the maximum brightness of white LEDs connected in parallel from a voltage source supply,
ballast resistor connected between each LED cathode and ground is required. Refer to the
application schematic in below Figure. The maximum brightness is determined by the forward
current(I
of a specific LED is usually stated in the typical characteristics of the given LED manufacturer's
datasheet. The correct ballast resistor value can be determined by the following quation:
Where: R
TM Technology Inc. reserves the right
to change products or specifications without notice.
APPLICATION INFORMATION
V
R
IN
B
2 .5 to 5V
=(V
V
E n ab le
OUT
V
F
I
OUT
) through the respective LED for a given forward voltage(V
F
F
B
=Desired LED forward current
=LED forward voltage at the desired forward current
CH
=Ballast resistor value in ohms
=Regulated charge pump output voltage
1 0u F
TE
-V
C
IN
F
)/I
F
V
E N
C +
IN
T 6 3 1 9A
C
G N D
FLY
1 uF
V
C -
O U T
C
1 0u F
O U T
R
D 1
B 1
P. 6
R
D 2
B 2
R
D 3
B 3
R
D 4
B 4
F
). The typical forward voltage
Publication Date: MAY. 2007
R
D 5
B 5
R
D 6
B 6
T6319A
Revision: A