A4975 PDF 데이터시트 ( Data ) - Allegro MicroSystems

부품번호

A4975 기능

기능

Full-Bridge PWM Microstepping Motor Driver

제조업체

Allegro MicroSystems

로고

A4975 데이터시트 를 다운로드하여 반도체의 전기적 특성과 매개변수에 대해 알아보세요.

전체 13 페이지

미리보기를 사용할 수 없습니다

A4975

Full-Bridge PWM Microstepping Motor Driver

Features and Benefits

▪ ±1.5 A continuous output current

▪ 50 V output voltage rating

▪ Internal PWM current control

▪ 3-bit nonlinear DAC

▪ Fast, mixed fast/slow, and slow current-decay modes

▪ Internal thermal shutdown circuitry

▪ Crossover-current and UVLO protection

Packages:

Package B, 16-pin DIP

with exposed tabs

Package LB, 16-pin SOIC

with internally fused pins

Not to scale

Description

The A4975 is designed to drive one winding of a bipolar

stepper motor in a microstepping mode. The outputs are

rated for continuous output currents to ±1.5 A and operating

voltages to 50V. Internal pulse width modulated (PWM) current

control combined with an internal three-bit nonlinear digital-

to-analog converter allows the motor current to be controlled

in full-, half-, quarter-, or eighth-step (microstepping) modes.

Nonlinear increments minimize the number of control lines

necessary for microstepping. Microstepping provides increased

step resolution, and reduces torque variations and resonance

problems at low speed.

Internal circuitry determines whether the PWM current-control

circuitry operates in a slow (recirculating) current-decay

mode, fast (regenerative) current-decay mode, or in a mixed

current-decay mode in which the off-time is divided into a

period of fast current decay and with the remainder of the

fixed off-time spent in slow current decay. The combination of

user-selectable current-sensing resistor and reference voltage,

digitally selected output current ratio; and slow, fast, or mixed

current-decay modes provides users with a broad, variable

range of motor control.

www.DataSheet.co.kr

Continued on the next page…

Functional Block Diagram

4975-DS

PHASE

VCC

10 15

VBB

GROUND

UVLO

& TSD

PFD 1

MIXED-DECAY

COMPARATOR

–

BLANKING

VCC

PWM LATCH

BLANKING

GATE

CURRENT-SENSE

COMPARATOR

–

w5 D/A

+–

VTH 2

8 9 14

SENSE

DISABLE

Datasheet pdf - http://www.DataSheet4U.net/

A4975

Full-Bridge PWM Microstepping Motor Driver

ELECTRICAL CHARACTERISTICS (continued) at TA = 25°C, VCC = 4.5 to 5.5 V (unless

otherwise noted.)

Characteristic

Symbol Test Conditions

Min.

Typ. Max.

Control Circuitry (cont’d)

Current-Sense Comparator Input

Offset Voltage*

VIO(S)

VREF = 0 V

— — ±5.0

Step Reference Current Ratio

Thermal Shutdown Temp.

Thermal Shutdown Hysteresis

SRCR

∆TJ

D0 = D1 = D2 = VIN(0)

D0 = VIN(1), D1 = D2 = VIN(0)

D0 = VIN(0), D1 = VIN(1), D2 = VIN(0)

D0 = D1 = VIN(1), D2 = VIN(0)

D0 = D1 = VIN(0), D2 = VIN(1)

D0 = VIN(1), D1 = VIN(0), D2 = VIN(1)

D0 = VIN(0), D1 = D2 = VIN(1)

D0 = D1 = D2 = VIN(1)

— 0—

— 19.5 —

— 38.2 —

— 55.5 —

— 70.7 —

— 83.1 —

— 92.4 —

— 100 —

— 165 —

— 15 —

AC Timing

PWM RC Fixed Off-time

tOFFRC CT = 470 pF, RT= 43 kΩ

18.2 20.2 22.3

PWM Minimum On Time

tON(min)

VCC = 5.0 V, RT ≥ 43 kΩ, CT = 470 pF,

IOUT = 100 mA

www.DataSheet.co.kr

0.8 1.6 2.2

* The total error for the VREF/VS function is the sum of the D/A error and the current-sense comparator input offset voltage.

Unit

°C

μs

Table 1 — PHASE Truth Table

PHASE

OUTA

OUTB

Table 2 — PFD Truth Table

VPFD

≥3.5 V

1.1 V to 3.1 V

≤0.8 V

Description

Slow Current-Decay Mode

Mixed Current-Decay Mode

Fast Current-Decay Mode

Table 3 — DAC Truth Table

DAC DATA

D2 D1 D0

HHH

Current

Ratio, %

100

VREF/VS

5.00

HH L

92.4

5.41

HLH

83.1

6.02

HLL

70.7

7.07

LHH

55.5

9.01

LHL

38.2 13.09

L LH

19.5 25.64

LLL

All Outputs Disabled

where VS = ITRIP×RS. See Applications section.

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Datasheet pdf - http://www.DataSheet4U.net/

4페이지

A4975

Full-Bridge PWM Microstepping Motor Driver

performance in microstepping applications.

For a given level of ripple current, slow decay affords the lowest

PWM frequency, which reduces heating in the motor and driver

IC due to a corresponding decrease in hysteretic core losses and

switching losses respectively. Slow decay also has the advantage

that the PWM load current regulation can follow a more rapidly

increasing reference before the PWM frequency drops into the

audible range. For these reasons slow-decay mode is typically

used as long as good current regulation can be maintained.

Under some circumstances slow-decay mode PWM can fail to

maintain good current regulation:

1) The load current will fail to regulate in slow-decay mode

due to a sufﬁciently negative back-EMF voltage in conjunction

with the low voltage drop across the load during slow decay

recirculation. The negative back-EMF voltage can cause the load

current to actually increase during the slow decay off time. A

negative back-EMF voltage condition commonly occurs when

driving stepping motors because the phase lead of the rotor

typically causes the back-EMF voltage to be negative towards

the end of each step (see ﬁgure 3A).

2) When the desired load current is decreased rapidly, the slow

rate of load current decay can prevent the current from following

the desired reference value.

3) When the desired load current is set to a very low value, the

current-control loop can fail to regulate due to its minimum duty

cycle, which is a function of the user-selected value of tOFF and

the minimum on-time pulse width ton(min) that occurs each time

the PWM latch is reset.

Fast Current-Decay Mode. When VPFD < 0.8 V, the

device is in fast current-decay mode (both the sink and source

drivers are disabled when the load current reaches ITRIP , and the

opposite pair is turned on). During the ﬁxed off-time, the load

inductance causes the current to ﬂow from ground to the load

supply via the motor winding and the opposite pair of transistors

(see ﬁgure 1). Because the full motor supply voltage is across

the load during fast-decay recirculation, the rate of load current

decay is rapid, producing a high ripple current for a given ﬁxed

off-time (see ﬁgure 2). This rapid rate of decay allows good

current regulation to be maintained at the cost of decreased

average current accuracy or increased driver and motor losses.

www.DataSheet.co.kr

A — Slow-Decay

B — Fast-Decay

C — Mixed-Decay

Figure 3 — Sinusoidal Drive Currents

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Datasheet pdf - http://www.DataSheet4U.net/

7페이지

구 성

총 13 페이지

다운로드

[ A4975.PDF 데이터시트 ]

Allegro MicroSystems에서 제조한 전자 부품 A4975은 전자 산업 및 응용 분야에서
광범위하게 사용되는 반도체 소자입니다.

A4975의 기능 및 특징 중 하나는 "Full-Bridge PWM Microstepping Motor Driver" 입니다.

일반적으로, Allegro MicroSystems에서 제조되는 전자부품들은 우수한 성능과
품질에 대한 신뢰성을 갖추고 있습니다.

구매 문의

일반 IC 문의 : 샘플 및 소량 구매
-----------------------------------------------------------------------

IGBT, TR 모듈, SCR 및 다이오드 모듈을 포함한
광범위한 전력 반도체를 판매합니다.

전력 반도체 전문업체

상호 : 아이지 인터내셔날

사이트 방문 : [ 홈페이지 ] [ 블로그 1 ] [ 블로그 2 ]

부품번호	상세설명 및 기능	제조사
A4970	Dual Full-Bridge PWM Motor Driver	Allegro MicroSystems
A4973	Full-Bridge PWM Motor Driver	Allegro MicroSystems

PDF 형식의 A4975 데이터시트 제공 ( 특징, 기능 )

관련 데이터시트