LP3954TLXSLASHNOPB datasheet(23/58 Pages) TI2

23 / 58 page

10 20 30 40 50 60 70 80 90 100

100

INPUT AMPLITUDE (%)

BLUE

GREEN

RED

5.00

0.05

GAIN (dB)

0.10

0.15

0.20

0.25

0.30

0.50

1.00

1.50

2.00

2.50

3.00

LP3954

www.ti.com

SNVS340D – JUNE 2005 – REVISED MARCH 2013

Figure 18. Overlapping mode MODE_CTRL[1:0] =

Figure 19. Peak Input Signal Level

[10]

Range vs Gain Setting

RGB OUTPUT SYNCHRONIZATION TO EXTERNAL CLOCK

The RGB pattern generator and high current flash driver timing can be synchronized to external clock with

following configuration.

1. Set PWM_SYNC bit in Enables register to 1

2. Feed PWM_SYNC pin with 5 MHz clock

By this the internal 5 MHz clock is disabled from pattern generator and flash timing circuitry.

The external clock signal frequency will fully determine the timings related to RGB and Flash.

Note: The boost converter will use internal 5 MHz clock even if the external clock is available.

RGB Driver Typical Performance Characteristics

RGB DRIVER ELECTRICAL CHARACTERISTICS (R1, G1, B1, R2, G2, B2 OUTPUTS)

Parameter

Test Conditions

Min

Typ

Max

Unit

ILEAKAGE

R1, G1, B1, R2, G2, B2 pin

0.1

µA

leakage current

IMAX(RGB)

Maximum recommended sink

CC mode

current(1)

SW mode

Accuracy at 37mA

RRGB=3.3 kΩ ±1%, CC mode

±5

Current mirror ratio

CC mode

1:100

RGB1 and RGB2 current

IRGB=37mA, CC mode

±5

mismatch

RSW

Switch resistance

SW mode

2.5

Ω

ƒRGB

RGB switching frequency

Accuracy proportional to internal

18.2

21.8

kHz

clock freq.

If external SYNC 5MHz is in use

kHz

(1)

Note: RGB current should be limited as follows:

constant current mode – limit by external RRGB resistor;

switch mode – limit by external ballast resistors

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