LP3933SL NSC [National Semiconductor], LP3933SL Datasheet - Page 14

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

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RSW1
GSW1
BSW1
RSW2
GSW2
BSW2
RGB_START
RGB_PWM
EN_FLASH1
EN_FLASH2
R1_PWM
G1_PWM
B1_PWM
R2_PWM
G2_PWM
B2_PWM
RGB LED PWM Control
PWM_LED input can be used as direct on/off or brightness (PWM) control. If PWM_LED input is not used, it must be tied to V
Note 15: Application Note 1291, “Driving RGB LEDs Using LP3933 Lighting Management System” contains a thorough description of the RGB driver functionality
including programming examples.
WLED Driver (WLED1...4)
White LED (WLED) driver drives each white LED with a
regulated constant current. The amount of the current is
controlled by the 8-bit current mode DAC from 0 to 25.5mA
in 0.1mA steps.
CLED Driver (CLED1…2)
The current of CLEDs (Caller ID display backlight LEDs) can
be adjusted by 8-bit current mode DAC. WLED and CLED
can be used to drive any kind of LED.
Enable for R1 switch
Enable for G1 switch
Enable for B1 switch
Enable for R2 switch
Enable for G2 switch
Enable for B2 switch
Master Switch for both RGB Drivers:
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)
Flash Mode enable controls for RGB1 and RGB2. In Flash mode (EN_FLASH = 1) RGB outputs are
PWM controlled simultaneously, not in 3-phase system as in the Normal Mode.
XX_PWM = 0 → External PWM control from PWM_LED pin is disabled
XX_PWM = 1 → External PWM control from PWM_LED pin is enabled
Internal PWM control (DUTY) can be used independently of external PWM control. External PWM has
the same effect on all enabled outputs.
RGB_START = 0 → RGB OFF
RGB_START = 1 → RGB ON, starts the new cycle from t = 0
(Note 15) (Continued)
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Enables
WLED and CLED enable is controlled from user register.
PWM control of WLED and CLED (for dimming etc.) is
possible using PWM_LED pin together with WLED_PWM
and CLED_PWM enable control from user register.
DD_IO
.
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