TC624 Microchip Technology Inc., TC624 Datasheet - Page 6

• Manufacturer Part Number: TC624
• Description: Low Cost Single Trip Point Temperature Sensor
• Manufacturer: Microchip Technology Inc.

TC622/TC624
4.0
4.1
The TC622 can be used to create a simple over-tem-
perature shutdown circuit. In this circuit, temperature is
sensed within the system enclosure (internal system
ambient) or at the heatsink itself. When measured
temperature exceeds a preset limit, a fault is indicated
and the system shuts down.
Figure 4-1 illustrates an over-temperature shutdown
circuit using the TC622 sensor in a single TO-220
package, allowing direct attachment to the heatsink
surface. As shown, the TC622 outputs are driven active
when the heatsink temperature equals the trip point
temperature set by R
crowbar circuit is activated, causing the supply output
to fold back to zero. The TC622 outputs remain active
until the heatsink temperature falls a minimum of 2°C
(built-in hysteresis) below the trip point temperature, at
which time the device again allows normal supply
operation.
FIGURE 4-1:
DS21440C-page 6
TC622 Heatsink Mounting
TYPICAL APPLICATIONS
Over-Temperature Shutdown
Output
Device
Circuit Board
TC622
TC622 Power Supply Over-Temperature Shutdown
TRIP
Heatsink
. When this happens, the
R
TRIP
V
CC
T
GND
SET
TC622
Heatsink Surface
4.2
The TC622/TC624 can be used to control a DC fan as
shown in Figure 4-2. The fan turns on when the sensed
temperature rises above T
temperature falls below T
Figure 4-3 shows the TC622 acting as a heater
thermostat. Circuit operation is identical to that of the
cooling fan application.
V
OUT
OUT
DD
Cooling and Heating Applications
Output Device
OVERTEMP
© 2006 Microchip Technology Inc.
SET
SET
Power Good
Signal
- 2°C.
and remains on until the
Crowbar
V
Circuit
OUT