AS1163 datasheet(42/91 Pages) AMSOSRAM

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AS1163

Functional description

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DS001075 • v2-00 • 2025-Nov-21

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6.7

PWM control

PWM engine has a resolution of 15 bits @ 500 Hz and 14 bits @ 1 kHz nominal frame rate,

while the PWM word is 16 bits including 1 extra bit for the dithering function.

The additional LSB can be used also for an automatic dithering functionality, where the LSB

value is toggled every frame. This can work with 14 bits or 15 bits PWM modes and also with

full dithering mode.

6.7.1

PWM LSB dithering (Auto dithering)

The engine cannot work natively with 16 bits, as the resulting PWM carrier frequency would be

too low for high quality lighting (ghosting, flicker effects).

An interpolation mechanism is provided, which automatically activates if the LSB is 1.

For example, if the 16-bit PWM register is set to 2, the PWM will execute the code 1 in 15-bit

word, furthermore, setting it to 3 will result in the alternate execution of codes 1 and 2 in a

15-bit word. Same behavior is followed in 1 kHz mode, when the PWM will use only 14-bit: In

this case the code 4 in 16-bit word will be executed as 1 in a 14-bit word, and the code 6 will

be executed alternatively with the codes 1 and 2 in 14-bit word (the LSB of the 16-bit word will

be discarded with the 1 kHz mode).

Information:

With 500 Hz mode, LSB dithering will be disabled if the register is written with 0xFFFF (it

would cause a wrap around) and with 0x0001 (it will cause continuous ON and OFF states of

the PWM driver).

With 1 kHz mode, LSB dithering will be disabled if the register is written with 0xFFFE and

0xFFFF (it would cause a wrap around) and with 0x0002 (it will cause continuous ON and OFF

states of the PWM driver).

AS1163 Datasheet(PDF) 42 Page - ams-OSRAM AG