NCV33033(2007) 데이터 시트보기 (PDF) - ON Semiconductor
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NCV33033 Datasheet PDF : 27 Pages
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MC33033, NCV33033
Sensor Phasing Comparison
There are four conventions used to establish the relative
phasing of the sensor signals in three phase motors. With six
step drive, an input signal change must occur every 60
electrical degrees, however, the relative signal phasing is
dependent upon the mechanical sensor placement. A
comparison of the conventions in electrical degrees is shown
in Figure 39. From the sensor phasing table (Figure 40), note
that the order of input codes for 60° phasing is the reverse of
300°. This means the MC33033, when the 60°/120° select
(Pin 18) and the FWD/REV (Pin 3) both in the high state
(open), is configured to operate a 60° sensor phasing motor
in the forward direction. Under the same conditions a 300°
sensor phasing motor would operate equally well but in the
reverse direction. One would simply have to reverse the
FWD/REV switch (FWD/REV closed) in order to cause the
300° motor to also operate in the same direction. The same
difference exists between the 120° and 240° conventions.
Rotor Electrical Position (Degrees)
0 60 120 180 240 300 360 420 480 540 600 660 720
SA
60° SB
SC
SA
120° SB
SC
SA
240° SB
SC
SA
300° SB
SC
Figure 39. Sensor Phasing Comparison
Sensor Electrical Phasing (Degrees)
60°
120°
240°
300°
SA SB SC SA SB SC SA SB SC SA SB SC
100101110111
110100100110
111110101100
011010001000
001011011001
000001010011
Figure 40. Sensor Phasing Table
In this data sheet, the rotor position has always been given
in electrical degrees since the mechanical position is a
function of the number of rotating magnetic poles. The
relationship between the electrical and mechanical position
is:
ǒ Ǔ Electrical Degrees + Mechanical Degrees
#Rotor Poles
2
An increase in the number of magnetic poles causes more
electrical revolutions for a given mechanical revolution.
General purpose three phase motors typically contain a four
pole rotor which yields two electrical revolutions for one
mechanical.
Two and Four Phase Motor Commutation
The MC33033 configured for 60° sensor inputs is capable
of providing a four step output that can be used to drive two
or four phase motors. The truth table in Figure 41 shows that
by connecting sensor inputs SB and SC together, it is possible
to truncate the number of drive output states from six to four.
The output power switches are connected to BT, CT, BB, and
CB. Figure 42 shows a four phase, four step, full wave motor
control application. Power switch transistors Q1 through Q8
are Darlington type, each with an internal parasitic catch
diode. With four step drive, only two rotor position sensors
spaced at 90 electrical degrees are required. The
commutation waveforms are shown in Figure 43.
Figure 44 shows a four phase, four step, half wave motor
controller. It has the same features as the circuit in Figure 37,
except for the deletion of speed adjust.
MC33033 (60°/120° Select Pin Open)
Inputs
Outputs
Sensor Electrical
Spacing* = 90°
SA
SB
F/R
1
0
1
1
1
1
0
1
1
0
0
1
Top Drives Bottom Drives
BT
CT
BB
CB
1
1
0
1
0
1
0
0
1
0
0
0
1
1
1
0
1
0
0
1
0
0
0
1
1
0
1
1
1
0
0
1
0
1
1
0
1
0
0
0
0
1
0
0
*With MC33033 sensor input SB connected to SC
Figure 41. Two and Four Phase, Four Step,
Commutation Truth Table
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