L6219DS(1996) Просмотр технического описания (PDF) - STMicroelectronics
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L6219DS Datasheet PDF : 10 Pages
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L6219
ELECTRICAL CHARACTERISTICS (Continued)
Symbol
PROTECTION
Parameter
Test Condition
TJ
Thermal Shutdown Temperature
Figure 1
Min. Typ. Max. Unit
-
170
-
°C
FUNCTIONAL DESCRIPTION
The circuit is intended to drive both windings of a
bipolar stepper motor.
The peak current control is generated through
switch mode regulation.
There is a choice of three different current levels
with the two logic inputs I01 - I11 for winding 1 and
I02 - I12 for winding 2.
The current can also be switched off completely
Input Logic (I0 and I1)
The current level in the motor winding is selected
with these inputs. (See fig. 2)
If any of the logic inputs is left open, the circuit will
treat it has a high level input.
Io
I1
Current Level
H
H No Current
L
H Low Current 1/3 Io max
H
L Medium Current 2/3 Io max
L
L Maximum Current Io max
Phase
This input determines the direction of current flow
4/10
in the windings, depending on the motor connec-
tions. The signal is fed through a Schmidt-trigger
for noise immunity, and through a time delay in
order to guarantee that no short-circuit occurs in
the output stage during phase-shift.
High level on the PHASE input causes the motor
current flow from Out A through the winding to
Out B
Current Sensor
This part contains a current sensing resistor (RS),
a low pass filter (RC, CC) and three comparators.
Only one comparator is active at a time. It is acti-
vated by the input logic according to the current
level chosen with signals Io and I1.
The motor current flows through the sensing re-
sistor RS.
When the current has increased so that the volt-
age across RS becomes higher than the refer-
ence voltage on the other comparator input, the
comparator goes high, which triggers the pulse
generator.
The max peak current Imax can be defined by:
Imax
=
Vref
10 Rs
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