参数资料
| 型号： | ADT7468ZEVB |
| 厂商： | ON Semiconductor |
| 文件页数： | 54/81页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL FOR ADT7468 |
| 标准包装： | 1 |
| 其它名称： | EVAL-ADT7468EB EVAL-ADT7468EB-ND |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页当前第54页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页第67页第68页第69页第70页第71页第72页第73页第74页第75页第76页第77页第78页第79页第80页第81页
ADT7468
Local = CYL = Bits <5:3> of Calibration Control Register 2
(Address = 0x37).
Remote 2 = CYR2 = Bits <7:6> of Calibration Control Register 2
CURRENT
TEMPERATURE
WAIT 2n
MONITORING
CYCLES
and Bit 0 of Calibration Control Register 1 (Address = 0x36).
Table 16. Cycle Bit Assignments
Duration
Duration
MEASUREMENT
T1(n)
OPERATING
POINT
TEMPERATURE
OP1
IS T1(n) > OP1
NO
YES
DECREASE T MIN
BY 1°C
Code
Short Cycle
(sec)
Long Cycle
(sec)
IS T1(n) < LOW TEMP LIMIT
000
001
010
011
100
8 cycles
16 cycles
32 cycles
64 cycles
128 cycles
1
2
4
8
16
16 cycles
32 cycles
64 cycles
128 cycles
256 cycles
2
4
8
16
32
AND
T MIN < HIGH TEMP LIMIT
AND
T MIN < OP1
AND
T1(n) > T MIN
NO
YES
INCREASE
T MIN BY 1°C
DO NOT
101
110
111
256 cycles
512 cycles
1024 cycles
32
64
128
512 cycles
1024 cycles
2048 cycles
64
128
256
Figure 72. Long Cycle Steps
CHANGE
Care should be taken when choosing the cycle time. A long
cycle time means that T MIN is updated less often. If your system
THERM LIMIT
HIGH TEMP
LIMIT
has very fast temperature transients, the dynamic T MIN control
loop will always be lagging. If you choose a cycle time that is too
OPERATING
POINT
HYSTERESIS
fast, the full benefit of changing T MIN might not be realized and
would need to change again on the next cycle. In effect, it is
overshooting. It is necessary to carry out some calibration to
identify the most suitable response time.
Figure 71 shows the steps taken during the short cycle.
WAIT n
MONITORING
CYCLES
CURRENT
TEMPERATURE
ACTUAL
TEMP
LOW TEMP
LIMIT
T MIN
Figure 73. Temperature Between Operating Point and Low Temperature Limit
Because neither the operating point minus the hysteresis
temperature nor the low temperature limit has been exceeded,
MEASUREMENT
T1(n)
OPERATING
POINT
TEMPERATURE
OP1
PREVIOUS
TEMPERATURE
MEASUREMENT
T1 (n – 1)
IS T1(n) >
(OP1 – HYS)
YES
IS T1(n) – T1(n – 1)
≤ 0.25°C
NO
YES
DO NOTHING
DO NOTHING
(SYSTEM IS
COOLING OF
FOR CONSTANT)
the T MIN value is not adjusted, and the fan runs at a speed
determined by the fixed T MIN and T RANGE values defined in the
automatic fan speed control mode.
Operating Point Exceeded—T MIN Reduced
When the measured temperature is below the operating point
NO
temperature minus the hysteresis, T MIN remains the same.
IS T1(n) – T1(n – 1) = 0.5 – 0.75°C
IS T1(n) – T1(n – 1) = 1.0 – 1.75°C
IS T1(n) – T1(n – 1) > 2.0°C
DECREASE T MIN BY 1°C
DECREASE T MIN BY 2°C
DECREASE T MIN BY 4°C
Once the temperature exceeds the operating temperature minus
the hysteresis (OP ? Hyst), T MIN starts to decrease. This occurs
Figure 71. Short Cycle Steps
Figure 72 shows the steps taken during the long cycle.
The following examples illustrate some of the circumstances
that might cause T MIN to increase, decrease, or stay the same.
Normal Operation—No T MIN Adjustment
during the short cycle (see Figure 71). The rate at which T MIN
decreases depends on the programmed value of n. It also
depends on how much the temperature has increased between
this monitoring cycle and the last monitoring cycle, that is, if
the temperature has increased by 1°C, then T MIN is reduced by
2°C. Decreasing T MIN has the effect of increasing the fan speed,
1.
2.
If measured temperature never exceeds the programmed
operating point minus the hysteresis temperature, then
T MIN is not adjusted, that is, remains at its current setting.
If measured temperature never drops below the low
temperature limit, then T MIN is not adjusted.
thus providing more cooling to the system.
If the temperature is slowly increasing only in the range
(OP ? Hyst), that is, ≤0.25°C per short monitoring cycle, then
T MIN does not decrease. This allows small changes in temp-
erature in the desired operating zone without changing T MIN .
The long cycle makes no change to T MIN in the temperature
range (OP ? Hyst), because the temperature has not exceeded
the operating temperature.
Rev. 3 | Page 54 of 81 | www.onsemi.com
相关PDF资料 |
PDF描述 |
|---|---|
| ADT7473ZEVB | BOARD EVALUATION FOR ADT7473 |
| ADT7475EBZEVB | BOARD EVALUATION FOR ADT7475 |
| ADT7476EBZEVB | BOARD EVALUATION FOR ADT7476 |
| ADT7490ZEVB | BOARD EVALUATION FOR ADT7490 |
| ADZS-21262-1-EZEXT | BOARD DAUGHTER FOR ADSP-21262 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ADT7470 | 制造商:AD 制造商全称:Analog Devices 功能描述:Temperature Sensor Hub and Fan Controller |
| ADT7470_13 | 制造商:AD 制造商全称:Analog Devices 功能描述:Temperature Sensor Hub and Fan Controller |
| ADT7470ARQ | 制造商:Analog Devices 功能描述:Temp Sensor Digital Serial (I2C) 16-Pin QSOP |
| ADT7470ARQ-REEL | 制造商:Rochester Electronics LLC 功能描述: 制造商:Analog Devices 功能描述: |
| ADT7470ARQ-REEL7 | 制造商:Analog Devices 功能描述:Temp Sensor Digital Serial (I2C) 16-Pin QSOP T/R |
发布紧急采购，3分钟左右您将得到回复。