Datasheet

SBOA102A
January 2005
Sensor-Emulator-EVM
System Reference Guide
13
10k
+
-
10k
+
-
10k
10k
+
-
+
-
X1
X1
Output of Sensor
Vin+ to Signal
Conditioning Chip
Output of Sensor
Vin-to Signal
Conditioning Chip
Input To Bridge
Vexc
(Excitation voltage)
200 ohm
10 ohm
10k
1k
100ohm
2k
Temperature
Signal V
T-
Temperature Signal
Output referenced
2
+
-
INA
Rt-
Diode
Rt+
Bridge Voltage Emulation
Rt-Temperature
Signal Emulation
U1d
U1b
U1c
U1A
U4
U5
U2
JUMP5
GND
Rt
R8
R9
R101
R102
R103
R104
R2401
R2402
R2403
R2404
Rt+ Temperature
Signal Emulation
(Not used in this mode)
Adjusted
to 1k
Adjusted
to 50
0.415V
0.415V
0.415V
0.415V
5.0V
5.0V
2.292V
150
Adjusted
to 5
50
2.305V
2.292V
2.305V
12.48mV
V
INP
V
INN
1.101k1.1078k
1.1023k
1.1075k
Temperature
Signal V
T
= 0.415V
Vexc = 5V
Note that the output signals of the
real world sensor and the emulator
are the same.
Rt-
Real World Sensor
100
V
DIF
= 12.4mV
JUMP1
Emulation Case 1: Rt-
(Resistance in the Bottom of The Bridge)
This diagram illustrates how the emulator generates the bridge output and temperature signals for the circuit where the sense resistor is connected to the bottom
of the bridge. Note how the output voltage of the temperature emulator (0.415V) is fed back to the bottom of the bridge emulator via the buffer circuit (U5 and
U1c), to emulate the bridge excitation change due to Rtin series with the bridge in the real world.
Figure 2.15