Jetson Xavier NX FAN behavior is weird

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
1

I designed the carrier board by referring to the document ‘Jetson_Xavier_NX_Product_Design_Guide_DG-09693-001_v1.7’.

image
image1156×401 37 KB

image
image1453×802 57.4 KB

Among them, the FAN circuit was designed by referring to the Design Guide of ‘Figure 12-7. Fan Connections’.

After installing Jetpack 5.1.2 I noticed the FAN behavior was weird.
The FAN rotates at low temperature to high speed and at high temperature to low speed.

The Developer Kit rotates normally at low temperatures and at high temperatures and at high speeds.

What is the difference between the two?

3

You should check the data sheet of your fan to find out if it has a reversal control logic.

4

FAN uses NVIDIA Genuine Cooler. Does Datasheet exist?

1

5

You use a NMOS for PWM pin design that is different to below devkit P3509 board design, and so the logic of PWM is inverted. The example design in Design Guide is just for reference, the real design depends on the Fan feature.

image
image2636×1587 302 KB

6

I designed it according to the Design Guide, but I think it is unreasonable for the FAN to operate strangely.

Can I invert PWM in my kernel or OS without H/W modifications?

7

You can refer to this topic for pwm_polarity. Jetson Xavier fan inverted - #2 by WayneWWW