Power Drivers for Peltier TEC Modules

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15

Applications Information

The MAX1968/MAX1969 typically drive a thermoelectric

cooler inside a thermal control loop. TEC drive polarity

and power are regulated based on temperature informa-

tion read from a thermistor, or other temperature-mea-

suring device to maintain a stable control temperature.

Temperature stability of 0.01

°C can be achieved with

carefully selected external components.

There are numerous ways to implement the thermal

loop. Figures 1 and 2 show a design that employs preci-

sion op amps, along with a DAC or potentiometer to set

the control temperature. The loop may also be imple-

mented digitally, using a precision A/D to read the ther-

mistor or other temperature sensor, a microcontroller to

implement the control algorithm, and a DAC (or filtered

PWM signal) to send the appropriate signal to the

MAX1968/MAX1969 CTLI input. Regardless of the form

taken by the thermal control circuitry, all designs are

similar in that they read temperature, compare it to a

set-point signal, and then send an error-correcting sig-

nal to the MAX1968/MAX1969 that moves the tempera-

ture in the appropriate direction.

Chip Information

TRANSISTOR COUNT: 2959

PROCESS: BiCMOS

Pin Configuration

28

27

26

25

24

23

22

21

20

19

18

17

16

15

1

2

3

4

5

6

7

8

9

10

11

12

13

14

MAXV

MAXIP

MAXIN

COMP

PGND1

LX1

OS1

PGND1

LX1

LX1

SHDN

CS

OS2

ITEC

FREQ

LX2

LX2

PGND2

LX2

PGND2

REF

CTLI

GND

TSSOP-EP

TOP VIEW

MAX1968

MAX1969

NOTE: GND IS CONNECTED TO THE UNDERSIDE METAL SLUG.