|
|
PDF A3986 Data sheet ( Hoja de datos )
| Número de pieza | A3986 | |
| Descripción | Dual Full-Bridge MOSFET Driver | |
| Fabricantes | Allegro MicroSystems | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de A3986 (archivo pdf) en la parte inferior de esta página. Total 16 Páginas | ||
|
No Preview Available !
www.DataSheet4U.com
A3986
Dual Full-Bridge MOSFET Driver
with Microstepping Translator
Features and Benefits
▪ 2-wire step and direction interface
▪ Dual full-bridge gate drive for N-channel MOSFETs
▪ Operation over 12 to 50 V supply voltage range
▪ Synchronous rectification
▪ Cross-conduction protection
▪ Adjustable mixed decay
▪ Integrated sinusoidal DAC current reference
▪ Fixed off-time PWM current control
Package: 38 pin TSSOP (suffix LD)
Description
The A3986 is a dual full-bridge gate driver with integrated
microstepping translator suitable for driving a wide range of
higher power industrial bipolar 2-phase stepper motors (typically
30 to 500 W). Motor power is provided by external N-channel
power MOSFETs at supply voltages from 12 to 50 V.
This device contains two sinusoidal DACs that generate the
reference voltage for two separate fixed-off-time PWM current
controllers.These provide current regulation for external power
MOSFET full-bridges.
Motor stepping is controlled by a two-wire step and direction
interface, providing complete microstepping control at full-,
half-, quarter-, and sixteenth-step resolutions. The fixed-off
time regulator has the ability to operate in slow-, mixed-, or
fast-decay modes, which results in reduced audible motor noise,
increased step accuracy, and reduced power dissipation.
The translator is the key to the easy implementation of this
IC. Simply inputting one pulse on the STEP input drives the
motor one step (full, half, quarter, or sixteenth depending on
the microstep select input). There are no phase-sequence tables,
high frequency control lines, or complex interfaces to program.
This reduces the need for a complex microcontroller.
Approximate size
Continued on the next page…
Typical Application Diagram
3986-DS, Rev. 1
1 page  
A3986
Dual Full-Bridge MOSFET Driver
with Microstepping Translator
ELECTRICAL CHARACTERISTICS, continued, at TA = 25°C, VDD = 5 V, VBB = 12 to 50V, unless noted otherwise
Characteristics
Symbol
Test Conditions
Min. Typ. Max. Units
Current Control
Blank Time
Fixed Off-Time
Reference Input Voltage
Internal Reference Voltage
Current Trip Point Error3
Reference Input Current1
Oscillator Frequency
Protection
VREG Undervoltage Lockout
VREG Undervoltage Lockout
Hysteresis
tBLANK
tOFF
VREF
VREFInt
EITRIP
IREF
fOSC
ROSC = 10 kΩ,
ROSC = 10 kΩ, , SR= High
20 kΩ to VDD
VREF = 2 V
ROSC = 10 kΩ
VREGUV Decreasing VREG
VREGUVHys
1.2 1.5 1.8 μs
18.12 – 23.16 μs
0.8 –
2V
1.9 2.0 2.1 V
– – ±5 %
–3 0
3 μA
3.2 4 4.8 MHz
7.5 8 8.5 V
100 200
– mV
VDD Undervoltage Lockout
VDD Undervoltage Lockout
Hysteresis
VDDUV Decreasing VDD
VDDUVHys
2.45 2.7 2.95 V
50 100
– mV
Overtemperature Shut Down
Overtemperature Shut Down
Hysteresis
TTSD
TTSDHys
Temperature increasing
Recovery = TTSD – TTSDHys
– 165 – ºC
– 15 – ºC
Control Timing
STEP Low Duration
STEP High Duration
Setup Duration
tSTEPL
tSTEPH
tSU
Input change to STEP pulse;
MS1, MS2, DIR
1–
1–
200 –
– μs
– μs
– ns
Hold Duration
tH
Input change from STEP pulse;
MS1, MS2, DIR
200 –
– ns
Wake Time Duration
tWAKE
1 – – ms
1For input and output current specifications, negative current is defined as coming out of (sourcing) the specified device pin.
2A RESET pulse of this duration will reset the translator to the Home position without entering Sleep mode.
3Current Trip Point Error is the difference between actual current trip point and the target current trip point, referred to full
scale (100%) current: EITRIP = 100 × (ITRIPActual – ITRIPTarget) / IFullScale %
Allegro MicroSystems, Inc.
5
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
5 Page 
A3986
Dual Full-Bridge MOSFET Driver
with Microstepping Translator
C1A, C1B, C2A, and C2B High-side connections for the
bootstrap capacitors, CBOOTx, and positive supply for high-
side gate drivers. The bootstrap capacitors are charged to
approximately VREG when the associated output Sxx terminal
is low. When the output swings high, the voltage on this ter-
minal rises with the output to provide the boosted gate volt-
age needed for the high-side N-channel power MOSFETs.
The bootstrap capacitor should be ceramic and have a value
of 10 to 20 times the total MOSFET gate capacitance.
GH1A, GH1B, GH2A, and GH2B High-side gate drive
outputs for external N-channel MOSFETs. External series
gate resistors can be used to control the slew rate seen at
the gate, thereby controlling the di/dt and dv/dt at the motor
terminals. GHxx = 1 (high) means that the upper half of the
driver is turned on and will source current to the gate of the
high-side MOSFET in the external motor-driving bridge.
GHxx =0 (low) means that the lower half of the driver is
turned on and will sink current from the external MOSFET’s
gate circuit to the respective Sxx pin.
S1A, S1B, S2A, and S2B Directly connected to the
motor, these terminals sense the voltages switched across the
load and define the negative supply for the floating high-side
drivers. The discharge current from the high-side MOSFET
gate capacitance flows through these connections which
should have low impedance traces to the MOSFET bridge.
GL1A, GL1B, GL2A, and GL2B Low-side gate drive
outputs for external N-channel MOSFETs. External series
gate resistors (as close as possible to the MOSFET gate)
can be used to reduce the slew rate seen at the gate, thereby
controlling the di/dt and dv/dt at the motor terminals.
GLxx = 1 (high) means that the upper half of the driver is
turned on and will source current to the gate of the low-side
MOSFET in the external motor-driving bridge. GLxx = 0
(low) means that the lower half of the driver is turned on and
will sink current from the gate of the external MOSFET to
the LSSx pin.
LSS1 and LSS2 Low-side return path for discharge of the
gate capacitors, connected to the common sources of the
low-side external FETs through low-impedance traces.
Motor Control
Motor speed and direction is controlled simply by two logic
inputs, and the microstep level is controlled by a further two
logic inputs. At power-up or reset, the translator sets the
DACs and phase current polarity to the initial Home state
(see figures 2 through 5 for home-state conditions), and sets
the current regulator for both phases to mixed-decay mode.
When a step command signal occurs on the STEP input, the
translator automatically sequences the DACs to the next
level (see table 3 for the current level sequence and current
polarity).
The microstep resolution is set by inputs MS1 and MS2 as
shown in table 1. If the new DAC level is higher or equal to
the previous level, then the decay mode for that full-bridge
will be slow decay. If the new DAC output level is lower
than the previous level, the decay mode for that full-bridge
will be set by the PFD1 and PFD2 inputs. This automatic
current-decay selection improves microstepping performance
by reducing the distortion of the current waveform due to the
motor BEMF.
STEP A low-to-high transition on the STEP input sequences
the translator and advances the motor one increment. The
translator controls the input to the DACs as well as the direc-
tion of current flow in each winding. The size of the incre-
ment is determined by the state of the MSx inputs.
MS1 and MS2 These Microstep Select inputs are used
to select the microstepping format, per table 1. Changes to
these inputs do not take effect until the next STEP input ris-
ing edge.
DIR This Direction input determines the direction of rotation
of the motor. When low, the direction is “clockwise” and
“counterclockwise” when high. A change on this input does
not take effect until the next STEP rising edge.
Internal PWM Current Control
Each full-bridge is independently controlled by a fixed off-
time PWM current control circuit that limits the load current
in the phase to a desired value, ITRIP. Initially, a diagonal pair
Allegro MicroSystems, Inc.
11
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
11 Page | ||
| Páginas | Total 16 Páginas | |
| PDF Descargar | [ Datasheet A3986.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| A3980 | Automotive DMOS Microstepping Driver with Translator | Allegro MicroSystems |
| A3980KLP | Automotive DMOS Microstepping Driver with Translator | Allegro MicroSystems |
| A3982 | DMOS Stepper Motor Driver |  Allegro |
| A3983 | DMOS Microstepping Driver | Allegro MicroSystems |
| 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 |