DRV102

17

SBVS009A

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FIGURE 18. (a) Constant Temperature Controller. (b) Improved Accuracy Constant Temperature Controller.

On/Off

Thermistor

DRV102

REF200

V

S

Heating

Element

Duty Cycle

Adjust

1

Delay

Adjust

2

Gnd

4

3

5

6

Out

12

0.1

µF

2

µF Film

7

2

3

4

6

100

µA

100

µA

1k

Ω

10k

Ω

10M

Ω

OPA134

or

Thermistor

5k

Ω at +25°C

20k

Ω

4.7V

Integrator improves accuracy

NOTE: (1) Or any common silicon diode suited

to the mechanical mounting requirements.

Temperature

Control

Higher temperature results

in lower duty cycle.

Higher temperature results

in lower duty cycle.

7, 8

R

1

R

2

0.1

µF

On/Off

DRV102

Heating

Element

Duty

Cycle

Adjust

a)

b)

1

Delay

Adjust

2

Gnd

4

3

5

V

S

V

S

6

Out

10

µF