as1720 austriamicrosystems, as1720 Datasheet - Page 8

• Manufacturer Part Number: as1720
• Description: Solenoid / Valve Driver With Current Limitation
• Manufacturer: austriamicrosystems

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
application shows how to drive 5W @12V relays.
This circuit is only applicable for AS1720A.
For this example with R1 = 100Ω and R
Figure 11. AS1720A - Typical Application
www.austriamicrosystems.com
100nF
VDDHV
VDDA
DUTY
Vsupply: +12V
ENN
Energising Current adjust
AS1720A
IE
S
120kΩ
I
= 2.5Ω the current Is is calculated as follows:
S
R
=
IE
10mA
I
1
×
Hold Current adjust
R
----- -
R
IH
1
S
Revision 1.03
=
0 01A
240kΩ
,
R
I
1
IH
×
100
-------- -
2 5 ,
OUT
VSS
=
100Ω
R1
400mA
LM741
1V
+
-
Relay
(see Figure 11)
I
R
BC161
S
S
can be used. This
Wheeling
Diode
Free-
(EQ 3)
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