TA8473F/FG/FN/FNG

2006-3-2

5

FG AND RD OUTPUTS

Both the FG and RD outputs are the open collector outputs.

The FG output is pulse proportional to the number of revolutions (the cycle is the same as OUT B) and the RD

output is at the GND level (actually, at Vsat (RD) level) when the motor is being driven and the RD output at

the potential level that is to be applied to the RD terminal as shown in Fig.2 is output when the motor is kept

restrained.

AUTOMATIC SELF ROTATION RECOVERY CIRCUIT

If the rotation of the fan motor is forced to stop by any physical power, the driving coil may be burnt as

inducing voltage caused when the motor is running disappears and large current flows to the driving coil.

Therefore, it becomes necessary to provide the fan motor with a circuit to prevent the driving coil from being

burned by detecting the forced stop of the motor rotation from the outside by some method and a circuit to

automatically rotate the motor when it is released from the restraint.

The TA8473F/FG and TA8473FN/FNG are ICs that have cleared the above problems by the burning preventive

automatic return circuit.

Fig. 2