Why different pulldown resistors for otherwise identical LED drivers?

[MLXXXp]

I was given a magnifying glass LED lamp that had stopped working. It appears that the 6 pin MCU in the controller has failed. I reverse engineered the controller and made a schematic.

The lamp has two rings of LEDs, one with "warm" and one with "cool" colour temperature, each driven by a separate MOSFET using PWM from MCU pins. What I find odd is that the pulldown resistor on the MOSFET gate is different for each. Otherwise, the circuits are identical. From measurements, the LED rings are also identical other than different phosphor colours in the LEDs.

One pulldown resistor (R13) is 150K and the other (R14) is 10K. I'm wondering why the difference?

I'm thinking it's a mistake, with one having the wrong value installed for some reason. If that's the case, what would be the proper intended value?

My feeling is that 150K would be sufficient. I think it's only to make sure the MOSFET is off during the time the MCU is powered up and the pins have defaulted to inputs, before the firmware configures them as PWM outputs.

The schematic is attached.

[Benta]

More likely that 10k is correct.
150k is way too high to turn off a MOSFET if it's PWM'ed.

[MLXXXp]

150k is way too high to turn off a MOSFET if it's PWM'ed.

As I said, it's only during MCU powerup/reset, when the MCU pins are defaulted as inputs, that the pulldown holds the gate low. Once the pins are configured as PWM outputs they will drive the gates both high and low.

[Benta]

150k is way too high to turn off a MOSFET if it's PWM'ed.

As I said, it's only during MCU powerup/reset, when the MCU pins are defaulted as inputs, that the pulldown holds the gate low. Once the pins are configured as PWM outputs they will drive the gates both high and low.

Many MCUs have I/O pullups, often in the 100k region. As you offer no information on this I can't help you further.

[MLXXXp]

Many MCUs have I/O pullups, often in the 100k region.

The MCU is dead and unmarked, so I can't identify it specifically. (I'm going to ask for help on that in a separate post).

Generally, if a MCU has pins that have weak pullups (or pulldowns), they can only be enabled when the pin is configured as an input. It make no sense to enable them when the pin is configured as an output, as it would be for PWM, because the drive current capability, and thus the output impedance, is far lower that the pullup or pulldown.

Anyway, thank you for offering your insights.