HMC1051/HMC1052/HMC1053
reasonable capability of measuring from tens of milliamperes to beyond 20 amperes of alternating or direct currents. See
application note AN-209 for the basic principles of current sensing using AMR bridges.
tempco
network
R
R
a
b
standoff distance
Vcc = 9Vdc
U1
R
th
.1µf
500k
-
RC4458
5.00k
5.00k
-
RC4558
+
output
+
U2
500k
Vcc/2 ~ +4.5Vdc
Figure 6
HMC1051
Current Sensor
Vcc =9Vdc
* Low ESR Tantalum
200Ω
1µf*
-
+
Iac
Idc
.1uf
set/reset
set/reset
Si1553DL
offset
U3
Conductor to be
Current Measured
Three Axis Compassing with Tilt Compensation
For full three-axis compassing, the circuit depicted in Figure 7 shows both a HMC1051 and a HMC1052 used for sensing
the magnetic field in three axes. Alternatively a single HMC1053 could be used for a single sensor package design. A
two-axis accelerometer with digital (PWM) outputs is also shown to provide pitch and roll (tilt) sensing, to correct the
three-axis magnetic sensors outputs into to the tilt-compensated two-axis heading. The accelerometer can be substituted
with a fluidic 2-axis tilt sensor if desired. For lower voltage operation with Lithium battery supplies (2.5 to 3.6Vdc), the
Set/Reset circuit should be upgraded from a single IRF7507 to the dual IRF7507 implementation (per Figure 2) to permit
a minimum 1-ampere pulse (500mA per set/reset strap resistance) to both the HMC1052 and HMC1051 sensors.
10
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