TC78B002FNG
2013-10-17
12
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
OUT1
OUT2
FG
RDO
Mode
H
L
L
PWM
OFF
L
Rotating (Note 1)
L
H
PWM
L
L
L
H
L
L
OFF
OFF
Current limit drive (Note 2)
L
H
OFF
L
L
OFF
OFF
OFF
Lock protection (Note 3)
OFF
OFF
Thermal shutdown
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)
With soft switching, with lead angle
Without soft switching,
without lead angle
HP
HM
OUT1
OUT2
FG
OUT1
OUT2
FG
0 < Hall < 5Hz
5Hz < Hall
