LP5526 datasheet(17/33 Pages) NSC

17 / 33 page

Functionality of Color LED

Outputs (RLED, GLED, BLED)

(Continued)

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.

R [%]

G [%]

B [%]

Total

current [%]

8.33

16.67

25.00

100

33.33

100

41.67

100

50.00

100

58.33

100

66.67

100

75.00

100

83.33

100

91.67

100

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.

•

Write the pre-flash current values to RGB max current

•

Enable RGB functions and disable PWM mode (EN-

_RGB = 1, RGB_PWM = 0)

•

Enable flash mode (EN_FLASH = 1), make sure

GPIO[0]/PWM pin is in low state

•

Enable external PWM pin (EN_PWM_PIN = 1)

•

Start pre-flash by switching on the LEDs (RSW = 1, GSW

= 1, BSW = 1). Pre-flash brightness can be affected also

by setting on only one or two LEDs

•

Use EN_EXT_R_PWM, EN_EXT_G_PWM and EN-

_EXT_B_PWM bits to select which LED outputs are used

for flash

•

Start flash pulse by setting GPIO[0]/PWM pin high and

stop it by setting GPIO[0]/PWM pin low

•

During the flash pulse the LED outputs with EN_EXT_x-

_PWM bit enabled give out maximum current, regardless

of RGB max current register value or XSW values

Note: EN_FLASH bit must be set low, and then high again

before it is possible to make a new flash pulse.

20179704

Using Flash Mode

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