AD7416/AD7417/AD7418
FAN CONTROLLER
Figure 14 shows a simple fan controller that will switch ON a
cooling fan when the temperature exceeds 80°C and switch it
OFF again when the temperature falls below 75°C. The AD7416
can be used standalone in this application or with a serial bus
interface if different trip temperatures are required. If the AD7416
is used with a bus interface, the sense of OTI can be set to active
high, Q1 and R1 can be omitted, and OTI can be connected
directly to the gate of Q2 with R2 as the pull-up resistor.
12V
VDD
3V TO 5.5V
AD7416
R1
10k⍀
R2
10k⍀
Q1
2N3904
OR SIMILAR
Q2
LOGIC LEVEL
MOSFET RATED
TO SUIT FAN
CURRENT
Figure 14. AD7416 Used as a Fan Controller
VDD
3V TO 5.5V
R1
10k⍀
THERMOSTAT
Figure 15 shows the AD7416 used as a thermostat. The heater
will be switched ON when the temperature falls below THYST
and switched OFF again when the temperature rises above
TOTI. For this application and for comparator mode, the OTI
output should be programmed active low.
VDD
3V TO
5.5V
HEATER
R1
10k⍀
RELAY
D1
1N4001 RLA1
AD7416
Q1
2N3904
OR SIMILAR
HEATER
SUPPLY
Figure 15. AD7416 Used as a Thermostat
SYSTEM WITH MULTIPLE AD7416S
The three LSBs of the AD7416’s serial address can be set by the
user, allowing eight different addresses from 1001000 to 1001111.
Figure 16 shows a system in which eight AD7416s are connected
to a single serial bus, with their OTI outputs wire-ANDed
together to form a common interrupt line. This arrangement
does mean that each device must be read to determine which
one has generated the interrupt, and if a unique interrupt is
required for each device, the OTI outputs can be connected
separately to the I/O chip.
Figure 16. Multiple Connection of AD7416s to a Single Serial Bus
100ns
CONVST
40s
Figure 17. CONVST When Temperature Channel Selected
100ns
CONVST
15s
Figure 18. CONVST When VIN Channel(s) Selected
–16–
REV. G