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POWER DISSIPATION CALCULATION

P

D +

V

CC

I

CC )

V

OUT

I

MAX

N

DCn

63

d

PWM

(2)

OPERATING MODES

SETTING DOT CORRECTION

I

OUTn +

Imax

DCn

63

(3)

TLC5941

SLVS589 – JULY 2005

The device power dissipation needs to be below the power dissipation rate of the device package to ensure

where:

N: number of OUTn driving LED at the same time

Table 3 shows the available operating modes. The TLC5941 GS operating mode (see Figure 10) and shift

register values are not defined after power up. One solution to solve this is to set dot correction data after

TLC5941 power up and switch back to GS PWM mode. The other solution is to overflow the input shift register

with 193 bits of dummy data and latch it while TLC5941 is in GS PWM mode.

Table 3. MODE Signal Truth Table

MODE

INPUT SHIFT REGISTER

OPERATING MODE

LOW

192 bit

Grayscale PWM Mode

HIGH

96 bit

Dot Correction Data Input Mode

The TLC5941 has the capability to fine-adjust the output current of each channel (OUT0 to OUT15)

independently. This is also called dot correction. This feature is used to adjust the brightness deviations of LEDs

connected to the output channels OUT0 to OUT15. Each of the 16 channels can be programmed with a 6-bit

where:

DCn = the programmed dot correction value for output n (DCn = 0 to 63).

n = 0 to 15

Dot correction data are entered for all channels at the same time. The complete dot correction data format

consists of 16 x 6-bit words, which forms a 96-bit wide serial data packet. The channel data is put one after

another. All data is clocked in with MSB first. Figure 7 shows the DC data format.

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