EVAL-ADT7462EBZ ON Semiconductor, EVAL-ADT7462EBZ Datasheet - Page 44

• Manufacturer Part Number: EVAL-ADT7462EBZ
• Description: BOARD EVALUATION FOR ADT7462
• Manufacturer: ON Semiconductor
• Type: Temperature Sensorr

Specifications of EVAL-ADT7462EBZ

• Contents: Evaluation Board
• For Use With/related Products: ADT7462
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

temperature, T
temperature starts to increase slowly, T
because the temperature increases at a rate of ≤0.25°C per
cycle.
Example 3: Temperature Below Low Limit, T
limit, T
T
therefore, more quietly. The long cycle diagram in Figure 69
shows the conditions that need to be true for T
increase. The following is a quick summary of those
conditions and the reasons they need to be true:
T
•
•
•
•
THERM LIMIT
HIGH TEMP LIMIT
OPERATING POINT
LOW TEMP LIMIT
Figure 71. Effect of Exceeding Operating Point Minus
MIN
MIN
When the temperature falls below the operating
When the temperature drops below the low temperature
The measured temperature has fallen below the low
temperature limit. This means the user must choose the
low limit carefully. It should not be so low that the
temperature never falls below it, because T
never increase and the fans would run faster than
necessary.
T
never allowed to increase above the high temperature
limit. As a result, the high limit should be sensibly
chosen, because it determines how high T
T
should never be allowed to increase above the operating
point temperature, because the fans do not switch on
until the temperature rises above the operating point.
The temperature is above T
control is turned off below T
T
MIN
MIN
MIN
may increase, if
has the effect of running the fan more slowly and,
HYSTERESIS
MIN
DECREASE HERE DUE TO
T1(n) – T1 (n – 1) ≤ 0.255C
is below the high temperature limit. T
is below the operating point temperature. T
EVERY SHORT CYCLE
SHORT CYCLE ONLY
DECREASES BY 15C
OR 0.755C = > T
may increase, as shown in Figure 72. Increasing
ACTUAL
TEMP
MIN
Hysteresis Temperature
MIN
stays the same. Even when the
DECREASE HERE DUE TO
T1(n) – T1 (n – 1) ≤ 0.255C
AND T1(n) > OP = > T
EVERY LONG CYCLE
DECREASES BY 15C
LONG CYCLE ONLY
MIN
MIN
. The dynamic T
.
DUE TO ANY CYCLE BECAUSE
MIN
NO CHANGE IN T
T1(n) – T1 (n – 1) ≤ 0.255C
AND T1(n) < OP = > T
MIN
STAYS THE SAME
stays the same,
MIN
MIN
MIN
MIN
can go.
Increased
would
MIN
is
MIN
MIN
MIN
http://onsemi.com
HERE
MIN
to
44
temperature is above T
limit, and T
below the operating point. When the temperature rises above
the low temperature limit, T
Example 4: Preventing T
for T
never switch on. As a result, T
within a specified range.
•
•
•
Enabling Dynamic T
enable/disable dynamic T
channels (see Table 39).
Dynamic T
the Remote 2 temperature channel. The chosen T
is dynamically adjusted based on the current temperature,
operating point, and high and low limits for this zone.
The T
behaves as described in the Automatic Fan Control
Overview section.
THERM LIMIT
HIGH TEMP LIMIT
OPERATING POINT
Figure 72 shows how T
Because T
Bits [1:0] of Dynamic T
Bit 1 (Remote 2 En) = 1 enables dynamic T
Bit 1 (Remote 2 En) = 0 disables dynamic T
The lowest possible value for T
T
If the temperature is below T
off or is running at minimum speed, and dynamic T
control is disabled.
LOW TEMP
Figure 72. Increasing T
MIN
THERM LIMIT
OPERATING POINT
LOW TEMP
HIGH TEMP LIMIT
MIN
T
Figure 73. T
MIN
MIN
LIMIT
T
cannot exceed the high temperature limit.
LIMIT
MIN
to reach full scale (191°C), because the fan would
HYSTERESIS
MIN
value chosen is not adjusted and the channel
MIN
MIN
ACTUAL
HYSTERESIS
TEMP
Control Register 1 (0x0B)
ACTUAL
TEMP
is below the high temperature limit and
is dynamically adjusted, it is undesirable
MIN
Temperature Limit
MIN
Adjustments Limited by High
MIN
Control Mode
MIN
MIN
MIN
MIN
and below the low temperature
MIN
MIN
from Reaching Full Scale
MIN
control on the temperature
increases when the current
MIN
Control Register 1 (0x0B)
for Quieter Operation
stays the same.
MIN
is allowed to vary only
, the fan is switched
T
FROM INCREASING
MIN
is −64°C.
PREVENTED
MIN
MIN
control on
MIN
control.
value
MIN