RGB LED PWM Control (Note 13) (Continued)

If ON=0,OFF=0 and RGB_PWM = 1, then RGB outputs are continuously on (no blinking), DUTY

controls the brightness and SLOPE is ignored.

If ON and OFF are the same, but not 0, RGB outputs are turned off.

CYCLE[1:0]

CYCLE sets the blinking cycle: [00] for 0.25s, [01] for 0.5s, [10] for 1s and [11] for 2s. CYCLE setting is

common to all R, G and B drivers.

RSW

GSW

BSW

Enable for R switch

Enable for G switch

Enable for B switch

RGB_START

Master Switch:

RGB_START = 0

→ RGB OFF

RGB_START = 1

→ RGB ON, starts the new cycle fromt=0

RGB_PWM

RGB_PWM = 0

→ RSW, GWS and BSW control directly the RGB outputs (on/off control only)

RGB_PWM = 1

→ Normal PWM RGB functionality (duty, slope, on/off times, cycle)

EN_FLASH

Flash Mode enable control for RGB. In Flash mode (EN_FLASH = 1) RGB outputs are PWM controlled

simultaneously, not in 3-phase system as in the Normal Mode.

EN_RED_PWM

EN_GREEN_PWM

EN_BLUE_PWM

EN_X_PWM = 0

→ External PWM control from RGB_EN pin is disabled

EN_X_PWM = 1

→ External PWM control from RGB_EN pin is enabled

Internal PWM control (DUTY) can be used independently of external PWM control. External PWM has

the same effect on all enabled colors.

Note 13: Application Note AN-1293, “Driving RGB LEDs Using LP3936 Lighting Management System” contains a thorough description of the RGB driver

functionality including programming examples.

WLED Drivers

White LED drivers drive each white LED with a regulated

constant current. The outputs are combined in two groups,

four outputs for the main display backlight and two outputs

for the sub display backlight. The current is controlled be-

tween 0 and 25.5 mA using the 8-bit current mode DA-

converters. WLED outputs can be used to drive any kind of

LED.

Main and sub display outputs have separate enable control

bits, EN_4LED and EN_2LED.

PWM control of WLED outputs for dimming or on/off control

is

possible

using

RGB_EN

pin

together

with

EN_4LED_PWM and EN_2LED_PWM enable control bits

from the user register. Recommended maximum frequency

of WLED external PWM control is 1 kHz.

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