[sdiy] Will LCD backlight PWM cause audio noise?

[Neil Johnson]

Tom Wiltshire wrote:
> Personal. I've still never done a commercial project with an LCD,
> though that might change one day.

That makes it easier then.... no need to worry about getting it through 
EMC testing then :)

Personally I would think about using a small PIC and keeping it and the 
LED driver on a small board as close to the LCD as possible, and send 
backlight commands over I2C or SPI.  That will keep the high frequency 
signals as far away as possible from the analogue voice circuits.  Also 
put a big ferrite on the wires going to the board to control any RF from 
it, especially at low or high backlight levels when the waveform will be 
short pulses.

Neil
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