LP5526TL NSC [National Semiconductor], LP5526TL Datasheet - Page 17

• Manufacturer Part Number: LP5526TL
• Description: Lighting Management Unit with High Voltage Boost Converter with up to 150mA Serial FLASH LED Driver
• Manufacturer: NSC [National Semiconductor]

Functionality of Color LED
Outputs (RLED, GLED, BLED)
When RLED, GLED and BLED are connected together as in
Typical Application 1, flash current can be adjusted with
8.33% step in constant current mode by changing RGB max
current register values as seen on following table. Note that
0% means that appropriate output is turned off by setting
RSW, GSW or BSW bit to 0.
(Continued)
I
R
100
25
50
75
0
0
0
0
0
0
0
0
[%]
I
G
100
100
100
100
100
25
50
75
0
0
0
0
[%]
I
B
100
100
100
100
100
100
100
100
100
25
50
75
[%]
current [%]
16.67
25.00
33.33
41.67
50.00
58.33
66.67
75.00
83.33
91.67
Total
8.33
100
Using Flash Mode
17
3. Using Flash Mode
In this mode Flash is triggered with external PWM pin and
pre-flash brightness is adjusted by adjusting the RGB max
current values. After flash pulse flash led will be shut down.
Note: EN_FLASH bit must be set low, and then high again
before it is possible to make a new flash pulse.
• Write the pre-flash current values to RGB max current
• Enable RGB functions and disable PWM mode (EN-
• Enable flash mode (EN_FLASH = 1), make sure
• Enable external PWM pin (EN_PWM_PIN = 1)
• Start pre-flash by switching on the LEDs (RSW = 1, GSW
• Use EN_EXT_R_PWM, EN_EXT_G_PWM and EN-
• Start flash pulse by setting GPIO[0]/PWM pin high and
• During the flash pulse the LED outputs with EN_EXT_x-
register
_RGB = 1, RGB_PWM = 0)
GPIO[0]/PWM pin is in low state
= 1, BSW = 1). Pre-flash brightness can be affected also
by setting on only one or two LEDs
_EXT_B_PWM bits to select which LED outputs are used
for flash
stop it by setting GPIO[0]/PWM pin low
_PWM bit enabled give out maximum current, regardless
of RGB max current register value or XSW values
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