Industrial Converter and Protector IC

AM460

analog microelectronics

April 2003

9/18

In 2-wire operation the IC ground is "virtual" (floating), as with a constant load resistance the supply voltage of

()

L

IN

OUT

S

CC

R

V

I

V

V

−

=

(4)

illustrated in Figure 3.

Setting the voltage gain using the voltage output

Using amplifier stages OP1 and OP3 for signal conditioning the overall gain can be set by selecting suitable ex-

and 2 as follows:

OP

GAIN

INP

OUT

G

G

V

V

⋅

⋅

=

(5)

Setting the output current range using the current output

When using amplification stage OP1 together with the V/I converter for signal conditioning the offset of the

verter pin VSET as shown in Figure 2 the values of the output current according to Equation 3 are as follows:

()

4

3

4

0

2

0

R

R

R

R

V

I

V

I

REF

SET

INDAI

OUT

+

⋅

=

=

=

(6)

1

2

0

4

3

−

=

SET

REF

I

R

V

R

R

(7)

SET

GAIN

INP

OUT

I

R

G

V

I

+

=

0

8

with

2

1

1

R

R

G

GAIN

+

=

(8)

Selecting the supply voltage

• When using voltage output pin VOUT the minimum V

V

5

≥

OUT

S

V

V

(9)