In the FLASH mode all the outputs are controlled in one

phase and the PWM period is 50 µs. The time averaged

FLASH mode current is three times the normal mode current

at the same DUTY value.

Blinking can be controlled separately for each output. On

and OFF times determine, when a LED turns on and off

within the blinking cycle. When both ON and OFF are 0, the

LED is on and doesn’t blink. If ON equals OFF but is not 0,

the LED is permanently off.

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Example Blinking Waveforms

RGB Driver Electrical Characteristics

(R

Symbol

Parameter

Conditions

Min

Typ

Max

Units

R

DS-ON

ON Resistance

2

4.5

Ω

I

LEAKAGE

Off State Leakage Current

V

0.04

1

µA

I

MAX

Maximum Sink Current

(Note 12)

120

mA

T

SMAX

Maximum Slope Period

Maximum Duty Setting

0.93

s

T

SMIN

Minimum Slope Period

Maximum Duty Setting

31

ms

T

SRES

Slope Resolution

Maximum Duty Setting

62

ms

T

START/STOP

Start/Stop Resolution

Cycle 1s

1/16

s

Duty

Duty Step Size

1/16

T

BLINK

Blinking Cycle Accuracy

−6

%

D

CYCF

Duty Cycle Range

EN_FLASH = 1

0

94

%

D

CYC

Duty Cycle Range

EN_FLASH = 0

0

31

%

D

RESF

Duty Resolution

EN_FLASH = 1 (4-bit)

6.27

%

D

RES

Duty Resolution

EN_FLASH = 0 (4-bit)

2.09

%

F

PWMF

PWM Frequency

EN_FLASH = 1

20

kHz

F

PWM

PWM Frequency

EN_FLASH = 0

6.67

kHz

Note 12: The total load current of the boost converter should be limited to 250 mA.

RGB LED PWM Control (Note 13)

RDUTY[3:0]

GDUTY[3:0]

BDUTY[3:0]

DUTY sets the brightness of the LED by adjusting the duty cycle of the PWM driver. The minimum DUTY

cycle [0000] is 0% and the maximum [1111] in the Flash mode is

the peak pulse current. The peak pulse current is determined by the external resistor, LED forward

voltage drop and the boost voltage.

RSLOPE[3:0]

GSLOPE[3:0]

BSLOPE[3:0]

SLOPE sets the turn-on and turn-off slopes. Fastest slope is set by [0000] and slowest by [1111]. SLOPE

changes the duty cycle at constant, programmable rate. For each slope setting the maximum slope time

appears at maximum DUTY setting. When DUTY is reduced, the slope time decreases proportionally. For

example, in case of maximum DUTY, the sloping time can be adjusted from 31 ms [0000] to 930 ms

[1111]. For 50% DUTY [1000] the sloping time is 17 ms [0000] to 496 ms [1111]. The blinking cycle has

no effect on SLOPE.

RON[6:0]

GON[6:0]

BON[6:0]

ON sets the beginning time of the turn-on slope. The on-time is relative to the selected blinking cycle

length. On-setting N (N = 0–127) sets the on-time to N/128 * cycle length.

ROFF[6:0]

GOFF[6:0]

BOFF[6:0]

OFF sets the beginning time of the turn-off slope. Off-time is relative to blinking cycle length in the same

way as on-time.

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