L6219DS View Datasheet(PDF) - Allegro MicroSystems
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L6219DS Datasheet PDF : 8 Pages
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L6219DS
DUAL FULL-BRIDGE
MOTOR DRIVER
LOGIC CONTROL OF OUTPUT CURRENT
Two logic level inputs (l and I ) allow digital selection of the motor
0
1
winding current at 100%, 67%, 33%, or 0% of the maximum level per
the table. The 0% output current condition turns off all drivers in the
bridge and can be used as an OUTPUT ENABLE function.
CURRENT-CONTROL TRUTH TABLE
l0
I1
Output Current
L
L
VREF/10 RS = ITRIP
H
L
VREF/15 RS = 2/3 ITRIP
L
H
VREF/30 RS = 1/3 ITRIP
H
H
0
These logic level inputs greatly enhance the implementation of
µP-controlled drive formats.
During
half-step
operations,
the
l
0
and
l
1
allow
the
µP
to
control
the
motor at a constant torque between all positions in an eight-step
TYPICAL APPLICATION
1
2
RS
3
RC
2
4
CC
5
6
FROM
µP
VREF
RT
7
8
99
10 θ2
11
12
CT
STEPPER
MOTOR
VBB
1
24
RS
23
RC
22
CC
21
VBB
+
20
19
18
17
θ1 16
15
14
VCC 13
FROM
µP
VREF
+5 V
CT
RT
Dwg. EP-008-2
sequence. This is accomplished by digitally
selecting 100% drive current when only one
phase is on and 67% drive current when two
phases are on. Logic highs on both l0 and l1
turn off all drivers to allow rapid current decay
when switching phases. This helps to ensure
proper motor operation at high step rates.
The logic control inputs can also be
used to select a reduced current level (and
reduced power dissipation) for ‘hold’ condi-
tions and/or increased current (and available
torque) for start-up conditions.
GENERAL
The PHASE input to each bridge
determines the direction motor winding
current flows. An internally generated
deadtime (approximately 2 µs) prevents
crossover currents that can occur when
switching the PHASE input.
All four drivers in the bridge output can
be
turned
off
between
steps
(l
0
=
l
1
≥
2.4
V)
resulting in a fast current decay through the
internal output clamp and flyback diodes. The
fast current decay is desirable in half-step and
high-speed applications. The PHASE, l0,and I1
inputs float high.
Varying the reference voltage (VREF)
provides continuous control of the peak load
current for microstepping applications.
Thermal protection circuitry turns off all
drivers when the junction temperature
reaches +170°C. It is only intended to protect
the device from failures due to excessive
junction temperature and should not imply
that output short circuits are permitted. The
output drivers are re-enabled when the
junction temperature cools to +145°C.
The L6219DS output drivers are opti-
mized for low output saturation voltages—less
than 1.8 V total (source plus sink) at 500 mA.
Under normal operating conditions, when
combined with the excellent thermal proper-
ties of the batwing package design, this
allows continuous operation of both bridges
simultaneously at 500 mA.
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