Datasheet

FUNCTIONALITY GUIDE — LED AND PERIPHERAL DRIVERS
L3
SM3
PGND3
4.7 Hm
PWM
LED_PWM
RED
BLUE
GREEN
P3
AGND0
A0
PWM
DRIVER
RGB
DRIVER
WHITELED
DRIVER
DISPLAY ANDI/O
SM3_SW
OUT
TPS65820
WHITELEDS
LSM3
EXTERNAL
PERIPHERALS
RGBLED
D1
R
10
FB3
W
C27
1 Fm
C18
100pF
FB3
TPS65820
www.ti.com .............................................................................................................................................................. SLVS663B – MAY 2006 – REVISED APRIL 2008
WHITE LED CONSTANT CURRENT DRIVER
Driver PWM Output LED Current Eff (%) Power Up
Voltage Default
Duty Cycle # of Steps Io(Typ) Max Acc (%)
Range
SM3 Off (0%), 256 5 V – 25 V Set by external resistor 25 mA 25 80 Off (0%)
0.4% -99.6%
Set via I
2
C
OPEN DRAIN PWM DRIVERS
Driver PWM Freq (kHz) PWM Duty Cycle Io(max) Power Up Default
mA
Range # of Steps Min Step
PWM 0.5/1/1.5/2/3/ 4.5/7.8/15.6 Off (0%), 8 6.25% 150 Off(0%)
Set via I
2
C 6.25% to 100
Set via I
2
C
LED_PWM 15.625 or 23.4 , set via I
2
C Off(0%), 256 0.4% 150 Off (0%)
0.4% to 99.6%
Set via I
2
C
RGB OPEN DRAIN LED DRIVER
Driver Flash Period (same for RGB) Flash On time (same for RGB) Brightness Io mA Power Up
(Individual R/G/B Control) Default
Range # of Min Step Range # of Min Step Duty (%) # of Min
Steps Steps Steps Steps
RED, No flash, 16 0.5 s 0.1 – 0.6 s 8 0.1 s Off (0%), 32 3.125% 0/4/8/12 Flash Off, 0
GREEN, or 1 – 8 s Set via I
2
C 3.125 to mA,
BLUE Set via I
2
C 96.87 0%
Set via I
2
C brightness
duty cycle
Figure 53. Required External Components, Recommended Values, External Connections
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