cui.com

date 08/15/2016

│ page 4 of 5

CUI Inc

│ SERIES: CFM-40 │ DESCRIPTION: DC AXIAL FAN

Figure 4 Duty Cycle

Auto Restart Protection/Current Limit Protection

When the fan motor is locked, the device will cut off the drive current within two to six seconds and restart automatically

after a few seconds. If the lock situation is continued, the device will work on a repeated cycle of cut-off and restart until

the lock is released. (See Figure 1 below).

APPLICATION NOTES

Figure 1 Current Limit Protection

Pulse Sensor/Tachometer Signal/FG

Pulse Sensor is for detecting the rotational speed of the fan motor. At locked rotor condition, the signal stops cycling and

the output is fixed at VoH or VoL (See Figures 2~3 below).

Vs=4~5 V

Figure 3 FG Signal Output Circuit:

Open Collector

Ic=10mA max

Figure 2 Output Waveform

PMW Control Signal

A speed control lead can be provided that will accept a PWM signal from the customer circuit to vary the speed of the fan.

The change in speed is linear by changing the Duty-Cycle of the PWM. Open collector type and pull-up voltage is changed

by maximum operating voltage and sink current by consuming current. (See Figure 4 below).

For more information, please visit the product page.