Some thoughts:
- Add another SY6280 current limiter for +5V and connect to VGA pin
9 (VESA power). Seems to be some difference of opinion on current requirements: 50mA[2], 300mA-1000mA[1]. If we were to limit at 300mA, it should easily supply the needs of I2C serial EEPROM and probably not over-tax our power supply.
I've also seen the VGA/HDMI +5V used to power various converters (most often, HDMI->VGA, but I imagine the inverse is sometimes used as well).
For VESA_SDA and VESA_SCL, add diode limiters connected to ground similar to ESD117-ESD123 on the SD bus lines provided the diode-limiting voltage is greater than VREFTTL nominal range. Otherwise use BAT54S connected between ground and VREFTTL.
Is it not possible that VESA_SDA and VESA_SCL are 5V? If so, they could require level shifting from 5V, am I wrong here?
Cheers! Arsenijs