|
|
PDF PBL3771 Data sheet ( Hoja de datos )
| Número de pieza | PBL3771 | |
| Descripción | Precision Stepper Motor Driver | |
| Fabricantes | Ericsson | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de PBL3771 (archivo pdf) en la parte inferior de esta página. Total 8 Páginas | ||
|
No Preview Available !
February 1999
PBL 3771/1
Precision Stepper Motor Driver
Description
The PBL 3771/1 is a switch-mode, constant-current driver IC (chopper) with two
channels, one for each winding of a two-phase stepper motor. The circuit is especially
developed for use in microstepping applications in conjunction with the matching dual
DAC (Digital-to-Analog Converter) PBM 3960. A complete driver system consists of
these two ICs, a few passive components and a microprocessor for generation of the
proper control and data codes required for microstepping.
The PBL 3771/1 contains a clock oscillator, which is common for both driver
channels; a set of comparators and flip-flops implementing the switching control; and
two H-bridges with internal recirculation diodes. Voltage supply requirements are +5 V
for logic and +10 to +45 V for the motor. Maximum output current is 650 mA per
channel.
A special logic function is used to select slow or fast current decay in the output
stage for improved high-speed microstepping.
The close match between the two driver channels guarantees consistent output
current ratios and motor positioning accuracy.
Key Features
• Dual chopper driver in a single
package.
• 650 mA output current per channel.
• Close matching between channels for
high microstepping accuracy.
• Selectable slow/fast current decay for
improved high-speed microstepping.
• Improved low-level linearity.
• Specially matched to Dual DAC
PBM 3960.
• Selection of packages, 22-pin
“batwing” DIP, 24 pin "batwing" SOIC
or 28-lead PLCC with lead-frame for
heat-sinking through PC board
copper.
Phase 1
CD1 VR1
PBL 3771/1
VCC
V
CC
C1
–
+
+
–
+
–
RC
–
+
+
–
E1
RQ
S
Logic
Logic
SQ
R
Phase 2
CD2 VR2
C2 GND
E2
Figure 1. Block diagram.
M A1
M B1
VMM1
VMM2
M B2
M A2
28-pin PLCC package
22-pin plastic DIP package
24-pin SO package
1
1 page  
PBL 3771/1
Functional Description
Each channel of the PBL 3771/1
consists of the following sections: an
H-bridge output stage, capable of driving
up to 650 mA continuous motor current
(or 500 mA, both channels driven), a
logic section that controls the output
transistors, an S-R flip-flop, and two
comparators. The oscillator is common
to both channels.
Constant current control is achieved
by switching the current to the windings.
This is done by sensing the (peak)
voltage across a current-sensing
resistor, RS, effectively connected in
series with the motor winding, and
feeding that voltage back to a
comparator. When the motor current
reaches a threshold level, determined by
the voltage at the reference input, VR,
the comparator resets the flip-flop, which
turns off the output transistors. The
current decreases until the clock
oscillator triggers the flip-flop, which
turns on the output transistors again,
and the cycle is repeated.
The current-decay rate during the
turn-off portion of the switching cycle,
can be selected fast or slow by the CD
input.
In slow current-decay mode, only one
of the lower transistors in the H-bridge
(those closest to the negative supply) is
switched on and off, while one of the
upper transistors is held constantly on.
During turn-off, the current recirculates
through the upper transistor (which one
depends on current direction) and the
corresponding free-wheeling diode
connected to VMM, see figure 5.
In fast current decay mode, both the
upper and lower transistors are
switched. During the off-time, the
freewheeling current is opposed by the
supply voltage, causing a rapid dis-
charge of energy in the winding.
Fast current decay may be required in
half- and microstepping applications
when rapid changes of motor current are
necessary. Slow current decay,
however, gives less current ripple, and
should always be selected, if possible, to
mini-mize core losses and switching
noise.
Applications Information
Current control
The output current to the motor winding
is mainly determined by the voltage at
the reference input and the value of the
sensing resistor, R .
S
Chopping frequency, winding
inductance, and supply voltage will affect
the current level, but to much less
extent. Fast current decay setting will
produce somewhat lower (average)
current than slow current decay. The
peak current through the sensing
resistor (and motor winding) can be
expressed as:
IM,peak = 0.18 • (VR / RS) [A]
i.e., with a recommended value of 1 ohm
for the sensing resistor, RS, a 2.5 V
reference voltage will produce an output
current of approximately 450 mA. To
improve noise immunity on the VR input,
the control range may be increased to
5 volts if R is correspondingly changed
S
to 2 ohms.
21
3
Rs
Motor Current
12
FAST Current Decay
SLOW Current Decay
3
Time
VCC (+5 V)
0.1 mF
0.1 mF
V MM
+
10 mF
11 3
20
7
V CC
Phase 1
V MM1
V MM2 MA1
8 CD1
9 VR1
MB1
PBL 3771/1
16 Phase 2
15 CD2
14 V R2
RC GND
12 5, 6,
+5 V 15 kW
17, 18
MA2
MB2
C1 E1
10 2
1 kW
C2
13
E2
21
1 kW
4
1
19
22
3 300 pF
GND
(VCC )
820 pF
1.0 W
820 pF
R S 1.0 W
RS
STEPPER
MOTOR
Pin numbers refer
to DIL package.
GND (VMM)
Figure 5. Output stage with current paths Figure 6. Typical stepper motor application with PBL 3771/1.
during turn -on, turn-off and phase shift.
5
5 Page | ||
| Páginas | Total 8 Páginas | |
| PDF Descargar | [ Datasheet PBL3771.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| PBL3770A | High Performance Stepper Motor Drive Circuit | Ericsson |
| PBL3770ANS | High Performance Stepper Motor Drive Circuit | Ericsson |
| PBL3770AQNS | High Performance Stepper Motor Drive Circuit | Ericsson |
| PBL3770AQNT | High Performance Stepper Motor Drive Circuit | Ericsson |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |