HMC1051/HMC1052/HMC1053
10 www.honeywell.com
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.
Duty Cycling for Lower Energy Consumption
For battery powered and other applications needing limited energy consumption, the sensor bridge and support
electronics can be switched off between magnetic field measurements. The HMC105X family of magnetic sensors are
very low capacitance (Bandwidth > 5MHz) sensor bridges and can stabilize quickly, typically before the support
electronics can. Other energy saving ideas would be to minimize the quantity of set/reset pulses which saves energy over
the battery life. Figure 8 shows a simple supply switching circuit that can be microprocessor controlled to duty cycle
(toggle) the electronics in moderate current (<25mA) applications.
HM C1052
U1
Vcc
offset
set/reset
.1uf
IR F7509
set/reset
Vcc/2
Vcc/2
5.00k
5.00k
500k
500k
5.00k
5.00k
500k
500k
LM V324
LM V324
1nf
1nf
U 3
U 4
3.3 to 5.0v
HM C1051
U 2
Vcc
Vcc/2
5.00k
5.00k
500k
500k
LM V324
.1 f
+
-
set/reset
C
with
M ultiplexed
A/D C onv.
AN 0
AN 1
AN 2
AN 3
Vcc/2
U 6
U 5
xout
yout
Tw o-axis
accelerom eter
Vcc
Vcc
DO 0
DI0
DI1
HM C1052
U 1
Vcc
offset
set/reset
.1uf
IR F7509
set/reset
Vcc/2
Vcc/2
5.00k
5.00k
500k
500k
5.00k
5.00k
500k
500k
LM V324
LM V324
1nf
1nf
U 3
U 4
3.3 to 5.0v
HM C1051
U 2
Vcc
Vcc/2
5.00k
5.00k
500k
500k
LM V324
.1 f
+
-
set/reset
C
w ith
M ultiplexed
A/D C onv.
AN 0
AN 1
AN 2
AN 3
Vcc/2
U 6
U 5
xout
yout
Tw o-axis
accelerom eter
Vcc
Vcc
DO 0
DI0
DI1
Figure 7
Three Axis Compass