Industrial V/I Converter and Protector IC

AM462

Analog Microelectronics GmbH

An der Fahrt 13, D – 55124 Mainz

Oktober 2007 – Rev.2.5 -Page 10/20

Phone: +49 (0)6131/91 073-0

Fax: +49 (0)6131/91 073-30

Internet:

http://www.analogmicro.de

Email: info@analogmicro.de

The working range resulting from Equation Fehler! Verweisquelle konnte nicht gefunden

werden. is described in Figure 4. Example calculations and typical values for the external

components can be found in the example applications from page 13 onwards.

Using OP2 as a current source

The additional operational amplifier OP2 can easily be connected up as a constant current source.

Using the circuit in Figure 5 the following applies:

Example : OP2 as courrent source

SET

SET

BG

S

R

R

V

I

V

27

.

1

=

=

(9)

The bridge symbol represents the component to be supplied with current (e.g. a piezoresistive

sensing element or temperature sensor).

A supply current of IS = 1mA is to be set. Using Equation Fehler! Verweisquelle konnte nicht

gefunden werden. the following value is calculated for external resistor RSET, which in turn

stipulates the size of the current:

Ω

=

=

=

k

27

.

1

mA

1

V

27

.

1

S

BG

SET

I

V

R

V

BG

AM462

OP2

1

R

SET

OP2 connected as

current source

2

I

S

Figure 5: Using OP2 as a constant current source