Datasheet

INA330
9
SBOS260
www.ti.com
FIGURE 6. PID Temperature Control Loop.
25°C. V
ADJ
= 2.5V + 0.9V will change the set-point by 1°C.
A 0V to 5V D/A converter will provide approximately ±2.5°C
adjustment range. A 12-bit D/A converter will allow for
approximately 0.001°C resolution on the set-point tempera-
ture.
For best temperature stability, the set-point temperature
voltage should be derived ratiometrically from V
BIAS
. A D/A
converter used to derive the set-point voltage should share
the same reference voltage source as V
BIAS
. Likewise, the 1V
INA330
+5V
(2)
V
2
1V
(1)
V
1
2
3
10
1
4
Enable
+5V
I
1
I
2
R
SET
10kΩ
R
G
200kΩ
Thermistor
R
SET
= 10kΩ
C
FILTER
500pF
I
O
= I
1
– I
2
V
O
8
7
V
ADJUST
= 0V to 5V
= 2.5V at 25°C Set-Point
D/A
Converter
Temperature
Adjust
V
REF
(1)
= +5V
R
1
R
3
R
2
OPA348
C
1
C
3
+5V
R
4
10kΩ
10kΩ
10kΩ
OPA569 OPA569
TEC
Cooling
C
2
PID
3.3V
3.3V
10kΩ
10kΩ
NOTES: (1) Ratiometrically derived voltages.
(2) The INA330 can also use a 3.3V, supply;
however, components must be chosen appropriate
to the smaller output voltage range.
✻ indicates direction of voltage change for
rising temperature at the thermistor.
TEC DRIVER AMPLIFIER OPTIONS
OPA569 2A Linear Amplifier
DRV591 3A PWM Power Driver
DRV593 3A PWM Power Driver
DRV594 3A PWM Power Driver
4kΩ
1kΩ
V
REF
(1)
+5V
10kΩ
10kΩ
V
REF
(1)
+5V
95 6
V
BIAS
(1)
2.5V
+–
➜
➜
➜
➜
✻
✻
➜
✻
➜
✻
source for V
1
and V
2
should be derived from the same
reference.
The PID loop compensation can be optimized for loop
stability and best response to thermal transients by adjusting
C
1
, C
2
, C
3
, R
2
, R
3
, and R
4
. This is highly dependant on the
thermal characteristics of the temperature-controlled block
and thermistor/TEC mounting. Figure 7 shows a circuit that
can be used as an intermediate circuit to easily adjust
components and determine system requirements.
FIGURE 7. Diagnostic and Optimization PID Temperature Control Loop.
C
2
1µF
R
7
10MΩ
R
6
5kΩ
INA330
+5V
+1V
Enable
+5V
R
SET
10kΩ
R
G
200kΩ
Thermistor
R
THERM
= 10kΩ
C
FILTER
500pF
V
ADJ
D/A
Converter
Ref
R
4
10kΩ
R
2
200Ω
R
1
2kΩ
V
BIAS
1/4
OPA340
R
3
10kΩ
C
1
22nF
R
8
10kΩ
1/4
OPA4340
R
10
100kΩ
R
11
10kΩ
1/4
OPA4340
R
9
100kΩ
C
3
1µF
V
BIAS
V
BIAS
V
BIAS
R
13
1MΩ
R
14
10kΩ
1/4
OPA4340
R
12
100kΩ
Differentiator
TC: 100ms to 1s
Integrator
TC: 1s to 10s
C
4
0.1µF
Power
Amplifier
OPA569
DRV591
DRV593
DRV594
To
TEC
1/2
OPA2340
R
15
10kΩ
Proportional
V
BIAS
R
5
5kΩ
V
1
V
2
3
2
1
10
75 6
8
7
4
I
1
I
2
This versatile PID compensation circuit allows
independent adjustment of the Proportional,
Integral, and Derivative control signals to
facilitate optimization of loop dynamics. The
results can then be duplicated using the circuit
shown in Figure 6.