TMP01FS-REEL7 Ver la hoja de datos (PDF) - Analog Devices

Número de pieza

componentes Descripción

Fabricante

TMP01FS-REEL7

Low Power Programmable Temperature Controller

Analog Devices 

TMP01

The last class of high power devices discussed here are

thyristors, which includes SCRs and Triacs. Triacs are a useful

alternative to relays for switching ac line voltages. The 2N6073A

shown in Figure 21 is rated to handle 4A (rms). The opto-

isolated MOC3011 Triac features excellent electrical isolation

from the noisy ac line and complete control over the high power

Triac with only a few additional components.

TEMPERATURE

VREF

1

SENSOR AND

VOLTAGE

VPTAT

V+ = 5V

8

R1

REFERENCE

300Ω

AC

LOAD

2

7 NC

R2

3

R3

4

WINDOW

COMPARATOR

HYSTERESIS

GENERATOR

TMP01

6

5 NC

1

6 150Ω

2 MOC9011 5

3

4

2N6073A

NC = NO CONNECT

Figure 21. Controlling the 2N6073A Triac

HIGH CURRENT SWITCHING

Internal dissipation due to large loads on the TMP01 outputs

causes some temperature error due to self-heating. External

transistors remove the load from the TMP01, so that virtually

no power is dissipated in the internal transistors and no self-

heating occurs. Figure 22 through Figure 24 show a few

examples using external transistors. The simplest case, using a

single transistor on the output to invert the output signal is

shown in Figure 22. When the open collector of the TMP01

turns on and pulls the output down, the external transistor Q1

base is pulled low, turning off the transistor. Another transistor

can be added to reinvert the signal as shown in Figure 23. Now,

when the output of the TMP01 is pulled down, the first transis-

tor, Q1, turns off and its collector goes high, which turns Q2 on,

pulling its collector low.

Thus, the output taken from the collector of Q2 is identical

to the output of the TMP01. By picking a transistor that can

accommodate large amounts of current, many high power

devices can be switched.

TEMPERATURE

1

VREF

SENSOR AND

VOLTAGE

VPTAT

8

R1

REFERENCE

2

7

R2

WINDOW

COMPARATOR

3

6

R3

4

HYSTERESIS

GENERATOR

5

TMP01

V+

4.7kΩ

IC

2N1711

Q1

Figure 22. An External Resistor Minimizes Self-Heating

TEMPERATURE

VREF

1

SENSOR AND

VOLTAGE

VPTAT

8

R1

REFERENCE

2

7

R2

WINDOW

COMPARATOR

3

6

R3

4

HYSTERESIS

GENERATOR

5

TMP01

V+

4.7kΩ

4.7kΩ

2N1711

IC

2N1711

Q1

Q2

Figure 23. Second Transistor Maintains Polarity of TMP01 Output

An example of a higher power transistor is a standard Darlington

configuration as shown in Figure 24. The part chosen, TIP-110,

can handle 2 A continuous which is more than enough to

control many high power relays. In fact, the Darlington itself

can be used as the switch, similar to MOSFETs and IGBTs.

12V

RELAY

MOTOR

SWITCH

TEMPERATURE

1

VREF

SENSOR AND

VOLTAGE

VPTAT

8

R1

REFERENCE

2

7

R2

WINDOW

COMPARATOR

3

6

R3

4

HYSTERESIS

GENERATOR

5

TMP01

V+

4.7kΩ

IC

TIP-110

4.7kΩ

2N1711

Figure 24. Darlington Transistor Can Handle Large Currents

Rev. E | Page 12 of 20

Share Link: