AS1720 Datasheet, PDF (1/12 Pages) ams AG – Solenoid / Valve Dr iver wi th Cur rent Limi tat ion

Datasheet
AS1720
Solenoid / Valve Driver with Current Limitation
1 General Description
The AS1720A is a low side current source providing an optimized
DC Operation for power saving and ultra low electromagnetic
radiation.
The AS1720B is a low side switch providing a PWM output, which
frequency is defined by an internal RC oscillator. The adjustable
PWM allows a fine control of the power delivered to the load.
Table 1. Standard Products
Model
Operation Mode
AS1720A
DC Current Source Operation
AS1720B
PWM Switching Operation
The AS1720A and AS1720B can be set to provide a strong initial
closure current and is automatically switching to hold mode for
power saving. The initial DC current, the hold current and the duty
cycle of the PWM can be adjusted by external resistors. An internal
thermal sensor prevents damage of the circuit due to excessive
heating up.
Both devices are optimized for driving electromechanical devices
such as valves, solenoids relays, actuators and positioners.
2 Key Features
Supply Range: +5V to +50V
Internal VDDA: 3.3V
Supply Current: 1 mA
Internal osc frequency: 30kHz
Fix delay: 136ms
Adjustable duty cycle: 20% – 90% (AS1720B only)
Adjustable energizing current: 10mA – 100mA
Adjustable hold current: 30% - 70% of energizing current
Current Limitation
Thermal shutdown: 150ºC
8-pin MLPD (2x2mm) Package
On request SOIC 8 Package (reduced temperature range -40°C
to +85°C)
3 Applications
The AS1720 is ideal for fluid and gas flow systems, industrial control,
electrical heaters, motor speed control.
Figure 1. AS1720 - Block Diagram
Vsupply: +5V to +50V
100nF
1
VDDHV
2
VDDA
R1
adjustable
Duty cycle
R2
3
DUTY
V_ref
LDO &
Ref Generator
Internal VDDA typ. 3.3V
AS1720
30kHz
Oscillator
Delay
PWM &
Control
VDDA
R_PU
Thermal
Shutdown
Current
Adjust
ENN 8
IE 6
IH 7
Off
RIE
On
Energising Current adjust
RIH
Hold Current adjust
www.austriamicrosystems.com/Solenoid-Relay-Driver/AS1720 Revision 1.04
L
Free-
Wheeling
RL
Diode
4
OUT
10nF
5
VSS
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