TC622EPA Просмотр технического описания (PDF) - Microchip Technology

Номер в каталоге

Компоненты Описание

производитель

TC622EPA

Low Cost Single Trip Point Temperature Sensor

Microchip Technology 

3.0 DETAILED DESCRIPTION

3.1 Trip Point Programming

When the temperature of the device exceeds the pro-

grammed temperature trip point, TSET, the OUT and

OUT outputs are driven into their active states. The

desired trip point temperature is programmed with a

single external resistor connected between the TSET

input and VCC. The relationship between the resistor

value and the trip point temperature is given by

Equation 3-1.

EQUATION 3-1:

RTRIP = 0.5997 x T 2.1312

Where:

RTRIP = Programming resistor value in Ohms

T = Desired trip temperature in degrees Kelvin.

For example, as shown in Figure 3-1, to program the

device to trip at 50°C, the programming resistor is:

RTRIP = 0.5997 x ((50 + 273.15)2.1312) = 133.65kΩ

FIGURE 3-1:

250

PROGRAMMING

RESISTOR VALUES VS.

TEMPERATURE

200

150

100

50

-55 -35 -15

5

25 45 65

TEMPERATURE (˚C)

85 105 125

TC622/TC624

3.2 Hysteresis

To prevent output “chattering” at the trip point tempera-

ture, the temperature detector in the TC622/TC624 has

2°C hysteresis (see Figure 3-2). The outputs are driven

active when the temperature crosses the set point

determined by the external resistor. As temperature

declines below the set point, the hysteresis action will

hold the outputs true until the temperature drops 2°C

below the threshold.

FIGURE 3-2:

TC622/TC624

HYSTERESIS

Temperature

Set Point

(Set Point – 2 Degrees C)

OUT

OUT

© 2002 Microchip Technology Inc.

DS21440B-page 5

Share Link: