MC33033 Motorola, MC33033 Datasheet - Page 18

• Manufacturer Part Number: MC33033
• Description: BRUSHLESS DC MOTOR CONTROLLER
• Manufacturer: Motorola

Three Phase Closed Loop Controller
speed control. For closed loop speed control, the MC33033
requires an input voltage proportional to the motor speed.
Traditionally this has been accomplished by means of a
tachometer to generate the motor speed feedback voltage.
Figure 37 shows an application whereby an MC33039,
powered from the 6.25 V reference (Pin 7) of the MC33033,
is used to generate the required feedback voltage without
the need of a costly tachometer. The same Hall sensor
signals used by the MC33033 for rotor position decoding are
utilized by the MC33039. Every positive or negative going
transition of the Hall sensor signals on any of the sensor
lines causes the MC33039 to produce an output pulse of
defined amplitude and time duration, as determined by the
external resistor R 1 and capacitor C 1 . The resulting output
18
The MC33033, by itself, is capable of open loop motor
10 k
0.01
Speed
Faster
100 k
F/R
5.1 k
10
4
1
2
3
5
9
4
6
7
8
1
2
3
MC33033
Close Loop
MC33039
1.0 M
0.1
Figure 37. Closed Loop Brushless DC Motor Control
14
13
12
11
20
19
18
17
16
15
6
1.0 k
1.0 k
8
5
7
4.7 k
With the MC33033 Using the MC33039
J 1
TP1
1.0 M
750 pF
R 1
C 1
Enable
1.1 k
1.0 k
1N5819
1N4742
MC33033
1.1 k
330
train of pulses present at Pin 5 of the MC33039 are
integrated by the Error Amplifier of the MC33033 configured
as an integrator, to produce a dc voltage level which is
proportional to the motor speed. This speed proportional
voltage establishes the PWM reference level at Pin 11 of the
MC33033 motor controller and completes or closes the
feedback loop. The MC33033 ouputs drive a TMOS power
MOSFET 3–phase bridge. High current can be expected
during conditions of start–up and when changing direction of
the motor.
having 120/240 degrees Hall sensor electrical phasing. The
system can easily be modified to accommodate 60/300
degree Hall sensor electrical phasing by removing the
jumper (J 1 ) at Pin 18 of the MC33033.
470
470
470
V M (18 to 30 V)
The system shown in Figure 37 is designed for a motor
0.1
1.1 k
0.1
0.1
33
100
MOTOROLA ANALOG IC DEVICE DATA
1000
0.05/1.0 W
TP2
S
Motor
N
N
S