LS7362 View Datasheet(PDF) - LSI Corporation
Part Name
Description
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LS7362 Datasheet PDF : 6 Pages
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6
O4
BRAKE 9
INPUT
7
O5
LS7362
5
COMMON
Vss
O6 8
BRAKE
MOTOR
SUPPLY
FIGURE 3.
SINGLE-ENDED
DRIVER CIRCUIT
This configuration requires only
one base current limiting resistor
connected from the COMMON
pin to Vss.
FORWARD
REVERSE
Inputs form SG1731
or UC1637
19
F/R
IN914
LS7362
10
ENABLE
2.2K
FROM MOTOR
POSITION
SENSOR
Vss
Vss
R1
15
S1
R3
R2
D1
C1
R4
R5
C3
R6
LS7362
C2
-
13
V TRIP
+
Vss
R8
Vss
C4
14
EXT. OSCILLATOR
R7
7362-101992-5
FIGURE 4. PRECISION CONTROL
BRUSHLESS DC MOTOR DRIVE
For controlled acceleration and deceleration of motors
in the forward or reverse directions, a motor control
pulse width modulator circuit such as the SG1731 or
UC1637 can be interfaced with the LS7362.
The logical OR gate made up of the resistor-diode net-
work permits the LS7362 to be enabled when either the
forward or reverse input is high. By applying the forward
input directly to Pin 19, the motor can only operate in the
forward direction when the forward input is high and only
in the reverse direction when the reverse input is high.
Motor direction is determined by relative pulse widths of
the forward and reverse inputs while acceleration or
deceleration is determined by variations of these widths.
FIGURE 5
CLOSED-LOOP SPEED CONTROLLER
A closed loop system can be configured by differentiating
one of the motor position sense inputs and integrating only
the negative pulses to form a DC voltage that is applied to
the inverting input of an op-amp. The non-inverting input
voltage is adjusted with a potentiometer until the resultant
voltage at V TRIP causes the motor to run at desired speed.
The R2-C1 differentiator, the R3-D1 negative pulse trans-
mitter and the R4-C2 integrator form a frequency to voltage
converter. An increase in motor speed above the desired
speed causes V TRIP to increase which lowers the duty cy-
cle modulation of the oscillator and the resultant motor
speed. A decrease in speed lowers V TRIP and raises the
duty cycle modulation and the resultant motor speed. For
proper operation, both R5 and R6 should be greater than
R4, and R4 in turn should be greater than both R2 and R3.
Also the R4-C2 time constant should be greater than the
R2-C1 time constant. C3 may be added across R6 for
additional V TRIP smoothing.
The information included herein is believed to be
accurate and reliable. However, LSI Computer Systems,
Inc. assumes no responsibilities for inaccuracies, nor for
any infringements of patent rights of others which may
result from its use.
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