11

The IM2000S will automatically change the non-recirculating pulse widths

to compensate for changes in supply voltage and accommodate a wide

variety of motor inductances. This method also allows for the use of very

low inductance motors, while utilizing a 20kHz chopping rate which

reduces motor heating but maintains high efficiency and low current

ripple.

Fixed PWM T ype

The internal PWM in the IM2000S may also be placed in a fixed

recirculating or non-recirculating mode by the use of the CIR0 and

CIR1 inputs. The relationship between the states of the CIR0 and

CIR1 inputs and the method of current control is shown in Table 3.3.

Table 3.3: Current Control Mode Settings

Power Contr ol Outputs

The relationship between the

Sine\Cosine, Power Section

Control and PWM outputs of

the IM2000S is illustrated in

Figure 3.5. When either the sine

or cosine is at 0, the enable and

all drive control outputs for that

particular phase will be turned

off to improve accuracy.

The inputs IHI and ILOW to the

IM2000S are used to invert the

polarity of the high side and low

side driver control signals

respectively. These inputs have

no effect on the sign, EN, and

PWM output signals.

Figure 3.5: Power Control Output Relationships

Sine\Cosine Output

Sense Current

Oscillator

Enable (In & Out)

HLx

HRx

LRx

SIGNx

PWMx

LLx

**

**

*Fast decay period for auto decay mode.

s

e

d

o

M

l

o

r

t

n

o

C

t

n

e

r

r

u

C

M

W

Ps

e

d

o

M

l

o

r

t

n

o

C

t

n

e

r

r

u

C

M

W

P

s

e

d

o

M

l

o

r

t

n

o

C

t

n

e

r

r

u

C

M

W

P

s

e

d

o

M

l

o

r

t

n

o

C

t

n

e

r

r

u

C

M

W

Ps

e

d

o

M

l

o

r

t

n

o

C

t

n

e

r

r

u

C

M

W

P

1

R

I

C1

R

I

C

1

R

I

C

1

R

I

C1

R

I

C

0

R

I

C0

R

I

C

0

R

I

C

0

R

I

C0

R

I

C

e

p

y

T

M

W

Pe

p

y

T

M

W

P

e

p

y

T

M

W

P

e

p

y

T

M

W

Pe

p

y

T

M

W

P

00

g

n

i

t

a

l

u

c

r

i

c

e

R

-

o

t

u

A

1

0

)

g

n

i

t

a

l

u

c

r

i

c

e

R

-

n

o

N

(

y

a

c

e

D

t

s

a

F

01

)

g

n

i

t

a

l

u

c

r

i

c

e

R

(

y

a

c

e

D

w

o

l

S

1

1

)

g

n

i

t

a

l

u

c

r

i

c

e

R

-

n

o

N

(

y

a

c

e

D

t

s

a

F

Figure 3.4: Non-Recirculating PWM

DRIVE CURRENT

FAST DECAY