Kontron KTH81/mITX - Fan Connectors (Cpu_Fan, Sys_Fan1, Sys_Fan2)

KTD-N0882-I Page 40 Internal Connectors
KTQ87/KTH81 Users Guide
7.3 Fan Connectors (CPU_Fan, SYS_Fan1, SYS_Fan2)
The SYS_FAN1 and SYS_Fan2 can be used to power, control and monitor fans for chassis ventilation etc.
The CPU_Fan is used for the connection of the FAN included in active CPU coolers.
The 4pin header is recommended to be used for driving 4-wire type Fan in order to implement FAN speed
control. 3-wire Fan support is also possible, but no fan speed control is integrated.
4-pin Mode:
3-pin Mode:
Signal Description
PWM PWM output signal for FAN speed control.
TACHO Tacho input signal from the fan, for rotation speed supervision RPM (Rotation Per Minute). The
signal shall be generated by an open collector transistor or similar. Onboard is a pull-up
resistor 4K7 to +12V. The signal has to be pulsed and onboard circuit is prepared for two pulses
per rotation.
12V +12V supply for fan. A maximum of 2000mA can be supplied from this pin.
GND Power Supply GND signal
Header
Pin
Signal
Description
Type
1
PWM
PWM output
O-3.3
2
TACHO
Tacho signal
I
3
12V
Power +12V
PWR
4
GND
Ground
PWR
Header
Pin
Signal
Description
Type
1
Not used
2
TACHO
Tacho signal
I
3
12V
Power +12V
PWR
4
GND
Ground
PWR