MC33035 Ver la hoja de datos (PDF) - ON Semiconductor
Número de pieza
componentes Descripción
Fabricante
MC33035 Datasheet PDF : 28 Pages
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MC33035, NCV33035
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 incre-
ments of approximately 10% from 0 to 90% on−time. Input codes 1010
through 1111 will produce 100% on−time or full motor speed.
Figure 33. Digital Speed Controller
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 volt-
age to that of the speed set to control the PWM.
Figure 34. Closed Loop Speed Control
ǒ Ǔ ǒ Ǔ VPin 3 + Vref
R3 ) R4
R1 ) R2
R2
R3
*
R4
R3
VB
8
ǒ Ǔ VB +
Vref
R5
R6
)
1
R5
R1
T
7
11
R3
R2
12
R3 §§ R5 ø R6
R6
R4
13
REF
25 μA
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, ex-
change the positions of R1 and R2.
Figure 35. Closed Loop Temperature Control
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16
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