MC33035 Просмотр технического описания (PDF) - Motorola => Freescale
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MC33035 Datasheet PDF : 24 Pages
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MC33035
Figure 31. Differential Input Speed Controller
REF
8
7
25 µA
VA R1
11
R2
EA
R3
12
ǒ Ǔ ǒ Ǔ VB
R4
13
PWM
+ )) * VPin 13
VA
R3
R1
R4 R2
R2 R3
R4
R3
VB
Figure 32. Controlled Acceleration/Deceleration
REF
8
Enable
7
R1
11
Increase
Speed
R2
12
C
13
25 µA
EA
PWM
Resistor R1 with capacitor C sets the acceleration time constant while R2
controls the deceleration. The values of R1 and R2 should be at least ten
times greater than the speed set potentiometer to minimize time constant
variations with different speed settings.
Figure 33. Digital Speed Controller
BCD
Inputs
5.0 V
16
VCC
12
P3
13
P2
14
P1
15
P0
Gnd
11
Q9 10
Q8
Q7 9
Q6 7
Q5 6
Q4 5
Q3 4
Q2 3
Q1 2
Q0 1
166 k
145 k
126 k
108 k
92.3 k
77.6 k
63.6 k
51.3 k
40.4 k
8
100 k 8
7
11
12
13
REF
25 µA
EA
PWM
The SN74LS145 is an open collector BCD to One of Ten decoder. When con-
nected as shown, input codes 0000 through 1001 steps the PWM in
increments of approximately 10% from 0 to 90% on–time. Input codes 1010
through 1111 will produce 100% on–time or full motor speed.
Figure 34. Closed Loop Speed Control
To Sensor
Input (Pin 4)
0.01
10 k
0.1
8
7
11
10 k
100 k
12
1.0 M
13
0.22 1.0 M
REF
25 µA
EA
PWM
The rotor position sensors can be used as a tachometer. By differentiating
the positive–going edges and then integrating them over time, a voltage
proportional to speed can be generated. The error amp compares this
voltage to that of the speed set to control the PWM.
ǒ Ǔ ǒ Ǔ Figure 35. Closed Loop Temperature Control
+ )) * VPin 3
Vref
R3
R1
R4
R2
R2
R3
R4
R3
VB
REF
ǒ Ǔ + ) VB
Vref
R5 1
8
R1 T
7
25 µA
R6
R5
11
§§ ø R3
R5 R6
R6
R3
R2
12
R4
13
EA
PWM
This circuit can control the speed of a cooling fan proportional to the difference
between the sensor and set temperatures. The control loop is closed as the
forced air cools the NTC thermistor. For controlled heating applications,
exchange the positions of R1 and R2.
14
MOTOROLA ANALOG IC DEVICE DATA
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