HMC1052L-TR Datasheet, PDF (9/11 Pages) Honeywell Accelerometers – 1, 2 and 3 Axis Magnetic Sensors

HMC1051/HMC1052/HMC1053
U1
Vcc
5.0v
HMC1051
set/reset
offset
Alternating or Direct Current Sensing
.1 f 500k
Vcc
5.00k
- _TLC072
5.00k
+
U2
500k
Vcc/2
10k pot
Threshold Set
- _TLC072
+
10k
Vcc
* Low ESR Tantalum
200
1 f*
-+
10k
output
LED
RLED
FMMT717
.1uf
FMMT617
0.1 f
0.1 f
set/reset
SR
10k
Figure 5
Magnetic Field Detector
The HMC105X family sensors can be utilized in a novel way for moderate to high current sensing applications using a
nearby external conductor providing the sensed magnetic field to the bridge. Figure 6 shows a HMC1051Z used as a
current sensor with thermistor element performing a temperature compensation function for greater accuracy over a wide
range of operational temperatures. Selection of the temperature compensation (tempco) resistors used depends on the
thermistor chosen and is dependant on the thermistor’s %/°C shift of resistance. For best op-amp compatibility, the
thermistor resistance should be above about 1000 ohms. The use of a 9-volt alkaline battery supply is not critical to this
application, but permits fairly common operational amplifiers such as the 4558 types to be used. Note that the circuit
must be calibrated based on the final displacement of the sensed conductor to the measuring bridge. Typically, an
optimally oriented measurement conductor can be placed about one centimeter away from the bridge and have
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.
standoff distance
R_b
tempco
network
R_a
Vcc = 9Vdc
U1
HMC1051
I_ac
I_dc
set/reset
offset
Conductor to be
Current Measured
.1 f 500k
R_th
5.00k
5.00k
- _RC4558
- _RC4458
+
output
+
U2
500k
Vcc/2 ~ +4.5Vdc
Figure 6
Current Sensor
* Low ESR Tantalum
1 f*
-+
Vcc =9Vdc
200
.1uf
set/reset
Si1553DL
U3
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