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부품번호 | 3951 기능 |
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기능 | FULL-BRIDGE PWM MOTOR DRIVER | ||
제조업체 | Allegro MicroSystems | ||
로고 | |||
전체 12 페이지수
3951
FULL-BRIDGE PWM MOTOR DRIVER
A3951SB
NC 1
REF/BRAKE 2
VBB
RC 3
GROUND 4
GROUND 5
LOGIC
SUPPLY
6
VCC
PHASE 7
ENABLE 8
LOGIC
VBB
16
LOAD
SUPPLY
15 OUTB
14 GROUND
13 GROUND
12 GROUND
11 SENSE
10 OUTA
LOAD
9 SUPPLY
Dwg. PP-056-1
ABSOLUTE MAXIMUM RATINGS
Load Supply Voltage, VBB ................... 50 V
Output Current, IOUT
(tw ≤ 20 µs) .................................. ±3.5 A
(Continuous) ............................... ±2.0 A
Logic Supply Voltage, VCC .................. 7.0 V
Logic Input Voltage Range,
VIN ........................ -0.3 V to VCC + 0.3 V
Sense Voltage, VSENSE ........................ 1.5 V
Reference Voltage, VREF ....................... VCC
Package Power Dissipation,
PD ....................................... See Graph
Operating Temperature Range,
TA ............................... –20°C to +85°C
Junction Temperature, TJ ............. +150°C*
Storage Temperature Range,
TS ............................. –55°C to +150°C
Output current rating may be limited by duty cycle,
ambient temperature, heat sinking and/or forced
cooling. Under any set of conditions, do not
exceed the specified current rating or a junction
temperature of +150°C.
* Fault conditions that produce excessive junction
temperature will activate device thermal shutdown
circuitry. These conditions can be tolerated but
should be avoided.
Designed for bidirectional pulse-width modulated current control of
inductive loads, the A3951SB and A3951SW are capable of continuous
output currents to ±2 A and operating voltages to 50 V. Internal fixed
off-time PWM current-control circuitry can be used to regulate the
maximum load current to a desired value. The peak load current limit is
set by the user’s selection of an input reference voltage and external
sensing resistor. The fixed off-time pulse duration is set by a user-
selected external RC timing network. Internal circuit protection includes
thermal shutdown with hysteresis, transient suppression diodes, and
crossover-current protection. Special power-up sequencing is not
required. The A3951SB and A3951SW are improved replacements for
the UDN2953B and UDN2954W, respectively. For new system de-
signs, the A3952SB/SEB/SLB/SW are recommended.
With the ENABLE input held low, the PHASE input controls load
current polarity by selecting the appropriate source and sink driver pair.
A user-selectable blanking window prevents false triggering of the PWM
current control circuitry. With the ENABLE input held high, all output
drivers are disabled.
When a logic low is applied to the BRAKE input, the braking
function is enabled. This overrides ENABLE and PHASE to turn off
both source drivers and turn on both sink drivers. The brake function
can be safely used to dynamically brake brush dc motors.
The A3951SB is supplied in a 16-pin dual in-line plastic package
with copper heat-sink contact tabs. The lead configuration enables
easy attachment of a heat sink while fitting a standard printed wiring
board layout. The A3951SW, for higher package power dissipation
requirements, is supplied in a 12-pin single in-line power-tab package.
In either package style, the batwing/power tab is at ground potential
and needs no isolation.
FEATURES
I ±2 A Continuous Output Current Rating
I 50 V Output Voltage Rating
I Internal PWM Current Control
I Internal Transient Suppression Diodes
I Under-Voltage Lockout
I Internal Thermal Shutdown Circuitry
I Crossover-Current Protection
I Default Brake Current Limit
Always order by complete part number:
Part Number
Package
A3951SB
A3951SW
16-Pin DIP
12-Pin Power-Tab SIP
RθJA
43°C/W
36°C/W
RθJT
6.0°C/W
2.0°C/W
3951
FULL-BRIDGE
PWM MOTOR DRIVER
ELECTRICAL CHARACTERISTICS (Continued)
Characteristic
Symbol Test Conditions
Control Logic
Logic Supply Voltage Range
Logic Input Voltage
Logic Input Current
Reference Voltage Range
Reference Input Current
Reference Voltage Divider Ratio
PWM RC Fixed Off Time
PWM Minimum On Time
Propagation Delay Time
VCC
VIN(1)
VIN(0)
IIN(1)
IIN(0)
VREF
IREF
–
toff
ton(min)
tpd
Operating
VIN = 2.0 V
VIN = 0.8 V
Operating
2.0 V ≤ VREF ≤ VCC
VREF = 5 V
CT = 1000 pF, RT = 20 kΩ
CT = 820 pF, RT ≥ 12 kΩ
CT = 1200 pF, RT ≥ 12 kΩ
IOUT = ±2.0 A, 50% EIN to 90% EOUT transition:
ENABLE on to source driver on
ENABLE off to source driver off
ENABLE on to sink driver on
ENABLE off to sink driver off
PHASE change to source driver on
PHASE change to source driver off
PHASE change to sink driver on
PHASE change to sink driver off
tpd(pwm)
Comparator trip to sink driver off
Thermal Shutdown Temperature
TJ
Thermal Shutdown Hysteresis
∆TJ
UVLO Disable Threshold
VCC(UVLO)
UVLO Hysteresis
∆VCC(UVLO)
Logic Supply Current
ICC(ON)
VENABLE = 0.8 V, VREF = 2.0 V
(No Load)
ICC(OFF)
VENABLE = VREF = 2.0 V
ICC(BRAKE) VREF = 0.8 V
NOTES: 1. Typical Data is for design information only.
2. Each driver is tested separately.
3. Negative current is defined as coming out of (sourcing) the specified device terminal.
Min.
Limits
Typ. Max. Units
4.5 5.0 5.5 V
2.0 – – V
– – 0.8 V
– <1.0 20 µA
– <-2.0 -200 µA
2.0 – VCC V
25 40 55 µA
9.5 10.0 10.5 –
18 20 22 µs
– 1.7 3.0 µs
– 2.5 3.8 µs
– 2.9 – µs
– 0.7 – µs
– 2.4 – µs
– 0.7 – µs
– 2.9 – µs
– 0.7 – µs
– 2.4 – µs
– 0.7 – µs
– 0.8 1.5 µs
– 165 – °C
– 15 – °C
3.15 3.50 3.85 V
300 400 500 mV
– 20 30 mA
– 12 18 mA
– 26 40 mA
115 Northeast Cutoff, Box 15036
4 Worcester, Massachusetts 01615-0036 (508) 853-5000
4페이지 3951
FULL-BRIDGE
PWM MOTOR DRIVER
VBB
between the duty cycle on the phase input and the aver-
age voltage applied to the motor is more linear than in the
case of ENABLE PWM control (which produces a discon-
tinuous current at low current levels). See also, “DC Motor
Applications” below.
RS
DRIVE CURRENT
RECIRCULATION
Dwg. EP-006-10
Figure 3 — Load-Current Paths
ENABLE Pulse-Width Modulation
Toggling the ENABLE input turns on and off the
selected source and sink drivers; the load inductance
causes the current to flow from ground to the load supply
via the ground clamp and flyback diodes (four-quadrant
operation or fast decay). See figure 3. When the device is
enabled, the internal current-control circuitry will be active
and can be used to limit the load current in the normal
internal PWM slow-decay or two-quadrant mode of opera-
tion.
MISCELLANEOUS INFORMATION
An internally generated dead time prevents crossover
currents that can occur when switching phase or braking.
Thermal protection circuitry turns off all drivers should
the junction temperature reach 165°C (typical). This is
intended only to protect the device from failures due to
excessive junction temperatures and should not imply that
output short circuits are permitted. The hysteresis of the
thermal shutdown circuit is approximately 15°C.
If the internal current-control circuitry is not used; the
VREF terminal should be connected to VCC, the SENSE
terminal should be connected to ground, and the RC
terminal should be left floating (no connection).
An internal under-voltage lockout circuit prevents
simultaneous conduction of the outputs when the device is
powered up or powered down.
ENABLE
I TRIP
LOAD
CURRENT
Dwg. WP-015-4
Figure 4 — ENABLE PWM Load-Current Waveform
PHASE Pulse-Width Modulation
Toggling the PHASE terminal determines/controls
which sink/source pair is enabled, producing a load current
that varies with the duty cycle and remains continuous at
all times. This can have added benefits in bidirectional
brush dc servo motor applications as the transfer function
APPLICATIONS NOTES
Current Sensing
The actual peak load current (IOUTP) will be greater
than the calculated value of ITRIP due to delays in the turn
off of the drivers. The amount of overshoot can be ap-
proximated as
IOUTP
≈
(VBB
–
((ITRIP
•
RLOAD) +
LLOAD
VBEMF))
•
tpd(pwm)
where VBB is the load/motor supply voltage, VBEMF is the
back-EMF voltage of the load, RLOAD and LLOAD are the
resistance and inductance of the load respectively, and
tpd(pwm) is the propagation delay as specified in the electrical
characteristics table.
The reference terminal has an equivalent input resis-
tance of 50 kΩ ±30%. This should be taken into account
when determining the impedance of the external circuit
that sets the reference voltage value.
www.allegromicro.com
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부품번호 | 상세설명 및 기능 | 제조사 |
3951 | FULL-BRIDGE PWM MOTOR DRIVER | Allegro MicroSystems |
3952 | FULL-BRIDGE PWM MOTOR DRIVER | Allegro MicroSystems |
DataSheet.kr | 2020 | 연락처 | 링크모음 | 검색 | 사이트맵 |