Keyboard LED driver PCA9532 is low-side, but schematics v0.6 assume it's push-pull
DMN3730U-7 is a NMOS, to conduct it needs a positive voltage applied on its gate. It is used to drive the keyboard LEDs (KB_RED, KB_GREEN, ... signals) through NXP PCA9532 datasheet, whose outputs are sinking/low-side/open-drain/switch-to-ground.
However, the current schematics seems to assume push-pull output, since no pullup (or pulldown) resistor is connected to the MOSFET gate (they ought to be placed anyway since a floating gate could inadvertently turn the MOSFET on via capacitive coupling). See page 13 (figure 14) of the PCA9532 datasheet for a reference.
Options are:
- use a push-pull driver -> to be identified
- use a PMOS instead of a NMOS and place it between VDD and LED -> perhaps the cleanest solution
- use 25 mA LEDs (maximum sunk current per PCA9532 output) and connect LEDs between VDD and PCA9532 with suitable current-limiting resistors -> they won't be very bright
- place a pullup to VDD on the gate -> this means that LEDs are switched OFF by PCA9532, and the pullup should be sized to avoid spending too much time in triode zone during switching-on.
P.S.: in schematics v0.6 when M3 (KB_RED-driven MOSFET) conducts KB_LED_VDD is shorted to ground. R232 (RED-) should have probably be connected to VLED- like GREEN- and BLUE- VLED- is C148 positive side, which is shorted to ground nonetheless by R239 0-ohm resistor.