Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 3 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS756
Chopper Stabilization Technique
Chopper Stabilization is an innovative circuit technique that is
This technique is made possible through the use of a BiCMOS
used to minimize the offset voltage of a Hall element and an asso- process that allows the use of low-offset and low-noise amplifiers
ciated on-chip amplifier. Allegro patented a Chopper Stabiliza-
tion technique that nearly eliminates Hall IC output drift induced
by temperature or package stress effects. This offset reduction
technique is based on a signal modulation-demodulation process.
Modulation is used to separate the undesired DC offset signal
from the magnetically induced signal in the frequency domain.
Then, using a low-pass filter, the modulated DC offset is sup-
pressed while the magnetically induced signal passes through
the filter. As a result of this chopper stabilization approach, the
output voltage from the Hall IC is desensitized to the effects
of temperature and mechanical stress. This technique produces
devices that have an extremely stable Electrical Offset Voltage,
are immune to thermal stress, and have precise recoverability
after temperature cycling.
in combination with high-density logic integration and sample
and hold circuits.
Regulator
Clock/Logic
Low-Pass
Filter
Hall Element
Amp
Concept of Chopper Stabilization Technique
Allegro MicroSystems, Inc.
115 Northeast Cutoff
9
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
