REV. B

TMP12

–11–

An example of a higher power transistor is a standard Darlington

configuration as shown in Figure 17. The part chosen, TIP-110,

can handle 2 A continuous, which is more than enough to con-

trol many high-power relays. In fact, the Darlington itself can be

used as the switch, similar to MOSFETs and IGBTs.

8

7

6

5

1

2

3

4

TEMPERATURE

SENSOR AND

VOLTAGE

REFERENCE

WINDOW

COMPARATOR

HYSTERESIS

GENERATOR

100

TMP12

VPTAT

4.7k

2N1711

V+

Q1

Figure 15. An External Transistor Minimizes Self-Heating

8

7

6

5

1

2

3

4

TEMPERATURE

SENSOR AND

VOLTAGE

REFERENCE

WINDOW

COMPARATOR

HYSTERESIS

GENERATOR

100

TMP12

VPTAT

4.7k

2N1711

V+

Q1

4.7k

2N1711

Q2

Figure 16. Second Transistor Maintains Polarity of TMP12

Output

8

7

6

5

1

2

3

4

TEMPERATURE

SENSOR AND

VOLTAGE

REFERENCE

WINDOW

COMPARATOR

HYSTERESIS

GENERATOR

100

TMP12

VPTAT

4.7k

2N1711

V+

4.7k

TIP-110

5V

MOTOR

SHUTDOWN

RELAY

12V

Figure 17. Darlington Transistor Can Handle Large Currents