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Functional Description
The equivalent circuit diagrams may be simplified or some parts of them may be omitted for explanatory purposes.
Timing charts may be simplified for explanatory purposes.
1.
Basic Operation
At startup, the motor is driven by a square-wave drive by determining the conducting phase with hall input
signal.
When hall signal frequency reaches 5Hz (typ) or more, the motor is driven by the conducting pattern which is
generated by estimating the next conducting timing from the hall input signal.
<I/O function table>
HP
HM
H
L
H
L
Note 1：Conducting phase is switched by the hall input signal. FG signal is outputted according to the phase-switching.
Conducting timing may be preceded depending on the lead angle set.
Note 2：Upper power transistor is turned off during current limitation. It recovers automatically every PWM frequency.
Note 3：FG output changes depending on the rotor position in the lock protection mode the same as rotating mode.
Timing chart (Normal rotation)
HP
HM
0 < Hall < 5Hz
OUT1
OUT2
FG
5Hz < Hall
OUT1
OUT2
FG
OUT1
OUT2
L
L
PWM
H
PWM
L
L
L
OFF
H
OFF
L
OFF
OFF
OFF
OFF
FG
RDO
OFF
L
Rotating (Note 1)
L
L
OFF
Current limit drive (Note 2)
L
OFF
Lock protection (Note 3)
Thermal shutdown
With soft switching, with lead angle
12
TC78B002FNG
Mode
Without soft switching,
without lead angle
2013-10-17
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