参数资料
| 型号： | ADT7475EBZEVB |
| 厂商： | ON Semiconductor |
| 文件页数： | 23/58页 |
| 文件大小： | 0K |
| 描述： | BOARD EVALUATION FOR ADT7475 |
| 产品变化通告： | MFG CHG Notification ADI to ON Semi |
| 标准包装： | 1 |
| 系列： | dBCool® |
| 类型： | 温度传感器 |
| 适用于相关产品： | ADT7475 |
| 所含物品： | 评估板 |
| 其它名称： | EVAL-ADT7475EB EVAL-ADT7475EB-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页当前第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页第54页第55页第56页第57页第58页
ADT7475
12 V
12 V
Because the MOSFET can handle up to 3.5 A, it is simply
TACH
ADT7475
10 k W
10 k W
TACH
4.7 k W
3.3 V
12 V, 4-WIRE FAN
V CC
TACH
PWM
a matter of connecting another fan directly in parallel with
the first. Care should be taken in designing drive circuits
with transistors and FETs to ensure that the PWM pins are
not required to source current and that they sink less than the
8 mA maximum current specified on the data sheet.
2 k W
PWM
Figure 32. Driving a 4-wire Fan
Driving Two Fans from PWM3
The ADT7475 has four TACH inputs available for fan
speed measurement but only three PWM drive outputs. If a
fourth fan is used in the system, it should be driven from the
PWM3 output in parallel with the third fan. Figure 33 shows
how to drive two fans in parallel using low cost NPN
transistors. Figure 34 shows the equivalent circuit using a
MOSFET.
12 V
Driving up to Three Fans from PWM3
TACH measurements for fans are synchronized to
particular PWM channels; for example, TACH1 is
synchronized to PWM1. TACH3 and TACH4 are both
synchronized to PWM3, so PWM3 can drive two fans.
Alternatively, PWM3 can be programmed to synchronize
TACH2, TACH3, and TACH4 to the PWM3 output. This
allows PWM3 to drive two or three fans. In this case, the drive
circuitry looks the same, as shown in Figure 36 and
Figure 37. The SYNC bit in Register 0x62 enables this
function.
Synchronization is not required in high frequency mode
when used with 4-wire fans.
Table 30. SYNC: ENHANCE ACOUSTICS REGISTER 1
(REG. 0X62)
3.3 V
3.3 V
Bit
Mnemonic
Description
ADT7475
1 k W
TACH3
TACH4
<4>
SYNC
1, Synchronizes TACH2, TACH3, and
TACH4 to PWM3.
PWM3
2.2 k W
Q1
MMBT3904
10 W
Q2
MMBT2222
TACH Inputs
Pin 4, Pin 6, Pin 7, and Pin 9, when configured as TACH
inputs, are open-drain TACH inputs intended for fan speed
measurement.
10 W
Q3
MMBT2222
Signal conditioning in the ADT7475 accommodates the
slow rise and fall times typical of fan tachometer outputs. The
maximum input signal range is 0 V to 3.6 V. In the event these
Figure 33. Interfacing Two Fans in Parallel to the
PWM3 Output Using Low Cost NPN Transistors
3.3 V
inputs are supplied from fan outputs that exceed 0 V to 3.6 V,
either resistive attenuation of the fan signal or diode clamping
must be included to keep inputs within an acceptable range.
Figure 35 to Figure 38 show circuits for most common fan
TACH outputs. If the fan TACH output has a resistive pullup
TACH4
10 k W
TYP
3.3 V
+V
+V
to V CC , it can be connected directly to the fan input, as shown
in Figure 35.
12 V V CC
ADT7475
TACH3
10 k W
TYP
TACH
3.3 V
5V
or
12 V
FAN
TACH
5V
or
12 V
FAN
PULLUP
4.7 k W
TYP
TACH
OUTPUT
FAN SPEED
PWM3
10 k W
TYP
Q1
NDT3055L
TACH
COUNTER
ADT7475
Figure 35. Fan with TACH Pullup to V CC
Figure 34. Interfacing Two Fans in Parallel to the
PWM3 Output Using a Single N-channel MOSFET
If the fan output has a resistive pullup to 12 V, or other
voltage greater than 3.6 V, the fan output can be clamped with
a Zener diode, as shown in Figure 36. The Zener diode voltage
should be chosen so that it is greater than V IH of the TACH
http://onsemi.com
23
相关PDF资料 |
PDF描述 |
|---|---|
| ADT7476EBZEVB | BOARD EVALUATION FOR ADT7476 |
| ADT7490ZEVB | BOARD EVALUATION FOR ADT7490 |
| ADZS-21262-1-EZEXT | BOARD DAUGHTER FOR ADSP-21262 |
| ADZS-BF-EZEXT-1 | BOARD DAUGHTER ADSP-BF533/561KIT |
| ADZS-BFAV-EZEXT | BOARD DAUGHT ADSP-BF533,37,61KIT |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ADT7476 | 制造商:AD 制造商全称:Analog Devices 功能描述:dBCool Remote Thermal Controller and Voltage Monitor |
| ADT7476A | 制造商:AD 制造商全称:Analog Devices 功能描述:dBCool Remote Thermal Controller and Voltage Monitor |
| ADT7476AARQZ | 功能描述:马达/运动/点火控制器和驱动器 MONITORS 5V/4 FANS RoHS:否 制造商:STMicroelectronics 产品:Stepper Motor Controllers / Drivers 类型:2 Phase Stepper Motor Driver 工作电源电压:8 V to 45 V 电源电流:0.5 mA 工作温度:- 25 C to + 125 C 安装风格:SMD/SMT 封装 / 箱体:HTSSOP-28 封装:Tube |
| ADT7476AARQZ-R | 功能描述:板上安装温度传感器 MONITORS 5V/4 FANS RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor |
| ADT7476AARQZ-REEL | 功能描述:IC REMOTE THERMAL CTRLR 24-QSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 热管理 系列:dBCool® 标准包装:1 系列:- 功能:温度监控系统（传感器） 传感器类型:内部和外部 感应温度:-40°C ~ 125°C，外部传感器 精确度:±2.5°C 本地（最大值），±5°C 远程（最大值） 拓扑:ADC，比较器，寄存器库 输出类型:2 线 SMBus? 输出警报:无 输出风扇:无 电源电压:2.7 V ~ 5.5 V 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:SOT-23-8 供应商设备封装:SOT-23-8 包装:Digi-Reel® 其它名称:296-22675-6 |
发布紧急采购，3分钟左右您将得到回复。