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AS1720

Datasheet - A p p l i c a t i o n I n f o r m a t i o n

9 Application Information

In order to drive relays, which need more than 100mA current, an external circuitry (see Figure 11) can be used. This application shows how to

drive 5W @12V relays.

This circuit is only applicable for AS1720A.

For this example with R1 = 100

Figure 11. AS1720A - Typical Application

(EQ 3)

I

S

I

1

R

1

R

S

------

×

0 01A

,

100

2 5

,

---------

×

400mA

=

=

=

BC161

100

Ω

LM741

Relay

VDDHV

Vsupply: +12V

IH

ENN

DUTY

IE

VSS

OUT

VDDA

100nF

AS1720A

1V

R1

10mA

120k

Ω

+

-

Free-

Wheeling

Diode

240k

Ω

Energising Current adjust

Hold Current adjust