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Электронный компонент: TC620CVOA

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2-15
TELCOM SEMICONDUCTOR, INC.
7
6
5
4
3
1
2
8
TC620
TC621
TC620/1-9 11/4/96
FUNCTIONAL BLOCK DIAGRAM
3
HIGH SET
2
LOW SET
5
CONTROL*
6
HIGH LIMIT
V
DD
7
LOW LIMIT
8
4
*Suffix code "C" denotes cooling option (high true CONTROL output);
suffix code "H" denotes heating option (low true CONTROL output).
Q
S
R
Q
+
+
TC620
HIGH SET
LOW SET
1
THERMISTOR
CONTROL*
HIGH LIMIT
LOW LIMIT
Temp
to
Voltage
Converter
V
REF
GEN
V
REF
GEN
V
REF
3
2
5
6
V
DD
7
8
4
Q
S
R
Q
+
+
TC621
Thermistor
Interface
Circuit
V
REF
GEN
V
REF
GEN
V
REF
Ambient
Part No.
Package
Temperature
TC621x*EOA
8-Pin SOIC
40
C to +85
C
TC621x*EPA
8-Pin Plastic DIP
40
C to +85
C
5V, DUAL TRIP POINT TEMPERATURE SENSORS
FEATURES
s
User-Programmable Hysteresis and Temperature
Set Point
s
Easily Programs with 2 External Resistors
s
Wide Temperature Detection
Range ................ 40
C to +125
C (TC620/621CVx)
s
External Thermistor for Remote Sensing
Applications (TC621x)
APPLICATIONS
s
Power Supply Overtemperature Detection
s
Consumer Equipment
s
Temperature Regulators
s
CPU Thermal Protection
ORDERING INFORMATION
Ambient
Part No.
Package
Temperature
TC620x*COA
8-Pin SOIC
0
C to +70
C
TC620x*CPA
8-Pin Plastic DIP
0
C to +70
C
TC620x*EOA
8-Pin SOIC
40
C to +85
C
TC620x*EPA
8-Pin Plastic DIP
40
C to +85
C
TC620CVOA
8-Pin SOIC
40
C to +125
C
TC621x*COA
8-Pin SOIC
0
C to +70
C
TC621x*CPA
8-Pin Plastic DIP
0
C to +70
C
*The part code will be C or H (see Functional Block Diagram, below,
and page 2).
GENERAL DESCRIPTION
The TC620 and TC621 are programmable logic output
temperature detectors designed for use in thermal manage-
ment applications. The TC620 features an on-board tem-
perature sensor, while the TC621 connects to an external
NTC thermistor for remote sensing applications.
Both devices feature dual thermal interrupt outputs
(HIGH LIMIT and LOW LIMIT), each of which program with
a single external resistor. On the TC620, these outputs are
driven active (high) when measured temperature equals the
user-programmed limits. The CONTROL (hysteresis) out-
put is driven high when temperature equals the high limit
setting, and returns low when temperature falls below the
low limit setting. This output can be used to provide simple
ON/OFF control to a cooling fan or heater. The TC621
provides the same output functions except that the logical
states are inverted.
The TC620/621 are usable over a maximum tempera-
ture range of 40
C to +125
C.
2-16
TELCOM SEMICONDUCTOR, INC.
ELECTRICAL CHARACTERISTICS:
T
A
= 25
C, unless otherwise specified.
Parameter
Conditions
Min
Typ
Max
Unit
Supply Voltage Range
4.5
--
18
V
Supply Current
5V
V
DD
18V
--
270
400
A
Output Resistance
Output High or Low, 5V
V
DD
18V
--
400
1000
Output Current
Temp Sensed
Source/Sink
--
--
1
mA
Output Current
Cool/Heat
Source/Sink
--
--
1
mA
Absolute Accuracy
T = Programmed Temperature
T 3
T
T + 3
C
ABSOLUTE MAXIMUM RATINGS*
Package Power Dissipation (T
A
70
C)
PDIP ............................................................... 730mW
SOIC ............................................................... 470mW
Derating Factors
Plastic ............................................................8mW/
C
Supply Voltage ............................................................ 20V
Input Voltage Any Input ....... (GND 0.3V) to (V
DD
+0.3V)
Operating Temperature
M Version ....................................... 55
C to +125
C
V Version ........................................ 40
C to +125
C
E Version .......................................... 40
C to +85
C
C Version ............................................... 0
C to +70
C
Maximum Chip Temperature ................................. +150
C
Storage Temperature ............................ 65
C to +150
C
Lead Temperature (Soldering, 10 sec) ................. +300
C
*Static-sensitive device. Unused devices must be stored in conductive
material. Protect devices from static discharge and static fields. Stresses
above those listed under "Absolute Maximum Ratings" may cause perma-
nent damage to the device. These are stress ratings only and functional
operation of the device at these or any other conditions above those
indicated in the operation sections of the specifications is not implied.
Exposure to absolute maximum rating conditions for extended periods may
affect device reliability.
V
DD
V
DD
GND
GND
LOW LIMIT
LOW LIMIT
CONTROL
CONTROL
NC
NC
LOW SET
LOW SET
HIGH SET
HIGH SET
HIGH LIMIT
HIGH LIMIT
V
DD
GND
LOW LIMIT
CONTROL
NC
LOW SET
HIGH SET
HIGH LIMIT
V
DD
GND
LOW LIMIT
CONTROL
NC
LOW SET
HIGH SET
HIGH LIMIT
8
7
6
5
1
2
3
4
1
8
2
7
3
6
4
5
TC621xCPA
TC621xEPA
TC621xCOA
TC621xEOA
8
7
6
5
1
2
3
4
1
8
2
7
3
6
4
5
TC620xCOA
TC620xEOA
TC620CVOA
TC620xCPA
TC620xEPA
PIN CONFIGURATIONS (DIP and SOIC)
5V, DUAL TRIP POINT
TEMPERATURE SENSORS
TC620
TC621
2-17
TELCOM SEMICONDUCTOR, INC.
7
6
5
4
3
1
2
8
DETAILED DESCRIPTION
The TC620/621 consists of a positive temperature coef-
ficient (PTC) temperature sensor, and a dual threshold
detector. Temperature setpoint programming is easily ac-
complished with external programming resistors from the
HIGH SET and LOW SET inputs to V
DD.
The HIGH LIMIT
and LOW LIMIT outputs remain low as long as measured
temperature is below setpoint values. As measured tem-
perature increases, the LOW LIMIT output is driven high
when temperature equals the LOW SET setpoint (
3
C
max). If temperature continues to climb, the HIGH LIMIT
output is driven high when temperature equals the HIGH
SET setpoint (Figure 1). The CONTROL (hysteresis) output
is latched in its active state at the temperature specified by
the HIGH SET resistor. CONTROL is maintained active until
temperature falls to the value specified by the LOW SET
resistor.
Programming The TC620
The resistor values to achieve the desired trip-point
temperatures on HIGH SET and LOW SET are calculated
using EQUATION 1 below:
R
TRIP
= 0.5997 x T
2.1312
Where: Rtrip = Programming resistor in Ohms
T
= The desired trip point temperature
in degrees Kelvin
Equation 1.
For example, a 50
C setting on either the HIGH SET or
LOW SET input is calculated using Equation 1 as follows:
R
set
= 0.5997 x ((50 + 273.15)
2.1312
) = 133.6k
Care must be taken to ensure the LOW SET program-
ming resistor is a smaller value than the HIGH SET program-
ming resistor. Failure to do this will result in erroneous
operation of the CONTROL output.
Care must also be taken to ensure the LOW SET
temperature setting is at least 5
C lower than the HIGH SET
temperature setting. That is:
LOW SET
HIGH SET 5
C
The nomograph of Figure 2 can help the user obtain an
estimate of the external resistor values required for the
desired LOW SET and HIGH SET trip points.
Built-in Hysteresis
To prevent output "chattering" when measured tem-
perature is at (or near) the programmed trip point values, the
LOW SET and HIGH SET inputs each have built-in hyster-
esis of 2
C below the programmed settings (Figure 3).
Figure 3: Built-in Hysteresis on Low Limit and High Limit Outputs
As shown, the outputs remain in their active state
(hysteresis) until temperature falls an additional 2
C below
the user's setting.
TEMPERATURE (
C)
RESISTANCE (k
)
-55
-35
-15
5
25
45
65
85
105
125
50
100
150
200
250
SET POINT
(SET POINT 2
C)
HIGH LIMIT
or LOW LIMIT
Output
Figure 1: TC620/621 Input vs. Output Logic
LOW SET POINT
HIGH SET POINT
LOW LIMIT OUTPUT
HIGH LIMIT OUTPUT
CONTROL OUTPUT (COOL OPTION)
CONTROL OUTPUT (HEAT OPTION)
TEMPERATURE
Figure 2. TC620 Sense Resistors vs. Trip Temperature
TC620
TC621
5V, DUAL TRIP POINT
TEMPERATURE SENSORS
2-18
TELCOM SEMICONDUCTOR, INC.
5V, DUAL TRIP POINT
TEMPERATURE SENSORS
TC620
TC621
Using The TC621
The TC621 operation is identical to that of the TC620,
but requires an external NTC thermistor. Use the resistance
versus temperature curve of the thermistor to determine the
values of the programming resistors. Note that the pin
numbers for the HIGH SET and LOW SET programming
resistors for the TC621 are reversed versus that of the
TC620 (i.e. the resistor value on HIGH SET [pin 2] should
always be lower than the one connected to LOW SET [pin
3]). Also note that the outputs of the TC621 are LOW TRUE
when used with an NTC thermistor.
TYPICAL NTC THERMISTOR
0
10
20
30
40
50
100
70
TEMPERATURE (
C)
0
50
60
150
200
250
300
350
THERMISTOR RESISTANCE (k
)
Figure 4. Typical Thermistor Resistance vs. Temperature
TC621 Thermistor Selection
The TC621 uses an external thermistor to monitor the
controlling temperature. A thermistor with a resistance value
of approximately 100k
at 25
C is recommended.
A temperature setpoint is selected by picking a resistor
whose value is equal to the resistance of the thermistor at the
desired temperature. For example, a 30k
resistor between
HIGH TEMP (pin 2) and V
DD
(pin 8) sets the high tempera-
ture trip point at +51
C and a 49k
resistor on LOW TEMP
(pin 3) sets the low temperature trip point to +41
C.
APPLICATIONS
Dual Speed Temperature Control
The Dual Speed Temperature Control uses a TC620
and a TC4469 quad driver. Two of the drivers are configured
in a simple oscillator. When the temperature is below the
LOW TEMP set point, the output of the driver is OFF. When
the temperature exceeds the LOW TEMP set point, the
TC4469 gates the oscillator signal to the outputs of the
driver. This square wave signal modulates the remaining
outputs and drives the motor at a low speed. If this speed
cannot keep the temperature below the HIGH TEMP set
point, then the driver turns on continuously which increases
the fan speed to high. The TC620 will monitor the tempera-
ture and only allow the fan to operate when needed, and at
the required speed to maintain the desired temperature. A
higher power option can be designed by adding a resistor
and a power MOSFET.
Temperature Controlled Fan
In this application, a high and a low temperature is
selected by two `set' resistors. The TC620 monitors the
ambient temperature and turns the FET switch on when the
temperature exceeds the HIGH TEMP set point. The fan
remains on until the temperature decreases to the LOW
TEMP set point. This provides the hysteresis. In this appli-
cation, the fan turns on only when required.
The TC621 uses an external thermistor to monitor the
ambient temperature. This adds one part, but allows more
flexibility in location of the sensor.
TC620/621 Outputs
Both devices have complimentary output stages. They
are rated at a source or sink current of 1mA maximum.
2-19
TELCOM SEMICONDUCTOR, INC.
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6
5
4
3
1
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8
TC620
HIGH TEMP
1
2
3
4
8
7
6
5
LOW TEMP
+12V
MTP3055E
FAN MOTOR
TC621
HIGH TEMP
1
2
3
4
8
7
6
5
LOW TEMP
+12V
MTP3055E
FAN MOTOR
THERMISTOR
(NTC)
Figure 6.
TC620
2
3
1
5
6
7
+12V
VMOTOR
MOSFET
FAN MOTOR
50
HIGHER POWER OPTION
1N4148
1N4148
8
4
TC4469
2
1
3
5
8
13
4
6
9
10
11
12
14
1M
10k
100k
FAN MOTOR
50 pF
TEMPERATURE SCALE
7
LOW TEMP
30 C
HIGH TEMP
50 C
10 F
0.1 F
30 C (FAN OFF)
50 C (FAN LOW)
UP (FAN HIGH)

1 F
0 C
30 C
50 C


Figure 5.
Figure 7. TC620 Heating/Cooling Application
TC620
1
2
3
4
8
7
6
5
TC4469
1
2
3
4
5
6
7
14
13
12
11
10
9
8
HIGH
TEMP
WARNING
HEATING/COOLING
EQUIPMENT
1k
1k
LOW
TEMP
WARNING
4.5V TO 18V
HIGH
TEMP
LOW
TEMP
TC620
TC621
5V, DUAL TRIP POINT
TEMPERATURE SENSORS
2-20
TELCOM SEMICONDUCTOR, INC.
TC620
TC621
5V, DUAL TRIP POINT
TEMPERATURE SENSORS
Figure 8. TC620 Heating/Cooling Application
TC620
1
2
3
4
8
7
6
5
TC4469
1
2
3
4
5
6
7
14
13
12
11
10
9
8
HIGH
TEMP
WARNING
HEATING/COOLING
EQUIPMENT
1k
1k
LOW
TEMP
WARNING
4.5V TO 18V
HIGH
TEMP
LOW
TEMP