LP3933SL NSC [National Semiconductor], LP3933SL Datasheet - Page 13

• Manufacturer Part Number: LP3933SL
• Description: Lighting Management System for Six White LEDs and Two RGB or FLASH LEDs
• Manufacturer: NSC [National Semiconductor]

R
I
I
T
T
T
T
Duty
T
D
D
D
D
F
F
LEAKAGE
MAX
R1DUTY[3:0]
G1DUTY[3:0]
B1DUTY[3:0]
R2DUTY[3:0]
G2DUTY[3:0]
B2DUTY[3:0]
R1SLOPE[3:0]
G1SLOPE[3:0]
B1SLOPE[3:0]
R2SLOPE[3:0]
G2SLOPE[3:0]
B2SLOPE[3:0]
R1ON[3:0]
G1ON[3:0]
B1ON[3:0]
R2ON[3:0]
G2ON[3:0]
B2ON[3:0]
R1OFF[3:0]
G1OFF[3:0]
B1OFF[3:0]
R2OFF[3:0]
G2OFF[3:0]
B2OFF[3:0]
CYCLE[1:0]
SMAX
SMIN
SRES
START/STOP
BLINK
PWMF
PWM
DS-ON
CYCF
CYC
RESF
RES
RGB Driver Electrical Characteristics
(R1, G1, B1, R2, G2, B2 outputs)
RGB LED PWM Control
Symbol
ON Resistance
Off State Leakage Current
Maximum Sink Current
Maximum Slope Period
Minimum Slope Period
Slope Resolution
Start/Stop Resolution
Duty Step Size
Blinking Cycle Accuracy
Duty Cycle Range
Duty Cycle Range
Duty Resolution
Duty Resolution
PWM Frequency
PWM Frequency
DUTY sets the brightness of the LED by adjusting the duty cycle of the PWM driver. The minimum duty
cycle is 0% [0000] and the maximum in the FLASH mode is
The peak pulse current is determined by the external resistor, LED voltage drop and the boost voltage. In
normal mode the maximum duty cycle is 33%.
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 [0111] the sloping time is 14 ms [0000] to 434 ms [1111]. The blinking cycle has
no effect on SLOPE.
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 = 0–15) sets the on-time to N/16 * cycle length.
OFF sets the beginning time of the turn-off slope. Off-time is relative to the blinking cycle length in the
same way as the on-time.
If ON = 0, OFF = 0 and RGB_PWM = 1, then RGB outputs are continuously on (no blinking), the DUTY
setting controls the brightness and the SLOPE setting is ignored.
If ON and OFF are the same, but not 0, the RGB outputs are turned off.
CYCLE sets the blinking cycle: [00] for 0.25s, [01] for 0.5s, [10] for 1s and [11] for 2s. CYCLE effects to
all RGB LEDs.
Parameter
(Note 15)
I = 75 mA
V
(Note 5)
At Maximum Duty Setting
At Maximum Duty Setting
At Maximum Duty Setting
Cycle 1s
FLASH_MODE = 1
FLASH_MODE = 0
FLASH_MODE = 1 (4 bit)
FLASH_MODE = 0 (4 bit)
FLASH_MODE = 1
FLASH_MODE = 0
FB
= 5V, LED driver off
Conditions
13
A
100% [1111] of the peak pulse current.
Min
−6
0
0
0.03
0.93
1/16
6.25
6.64
2.21
6.67
Typ
3.5
±
31
62
20
3
Max
99.6
33.2
120
+6
6
1
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Units
kHz
kHz
mA
ms
ms
µA
%
%
%
%
%
%
Ω
s
s