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參數(shù)資料
| 型號： | MAX6639AEE+ |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 模擬信號調理 |
| 英文描述： | 2-Channel Temperature Monitor with Dual, Automatic, PWM Fan-Speed Controller |
| 中文描述： | SPECIALTY ANALOG CIRCUIT, PDSO16 |
| 封裝： | QSOP-16 |
| 文件頁數(shù)： | 9/22頁 |
| 文件大?。?/td> | 189K |
| 代理商： | MAX6639AEE+ |
the circuit in Figure 8 can be used to eliminate pulse
stretching while still allowing accurate tachometer feed-
back. The diode connects the fan to a low-voltage
power supply, which keeps the fan’s internal circuitry
powered even when the PWM drive is zero. Therefore,
the tachometer signal is always available and pulse
stretching can be turned off. Note that this approach
prevents the fan from turning completely off, so even
when the duty cycle is 0%, the fan may still spin.
Linear Fan Supply Drive
While many fans are compatible with PWM power-supply
drive, some are excessively noisy with this approach.
When this is the case, a good alternative is to control the
fan’s power-supply voltage with a variable DC power-sup-
ply circuit. The circuit in Figure 10 accepts the PWM sig-
nal as an input, filters the PWM, and converts it to a DC
voltage that then drives the fan. To minimize the size of
the filter capacitor, use the highest available PWM fre-
quency. Pulse stretching is not necessary when using a
linear fan supply. Note that this approach is not as effi-
cient as PWM drive, as the fan’s power-supply current
flows through the MOSFET, which can have an apprecia-
ble voltage across it. The total power is still less than
that of a fan running at full speed. Table 11 is a summa-
ry of fan-drive options.
4-Wire Fans
Some fans have an additional, fourth terminal that
accepts a logic-level PWM speed-control signal as
shown in Figure 10. These fans require no external
power circuitry and combine the low noise of linear
drive with the high efficiency of PWM power-supply
drive. Higher PWM frequencies are recommended
when using 4-wire fans.
MAX6639/MAX6639F
2-Channel Temperature Monitor with Dual,
Automatic, PWM Fan-Speed Controller
______________________________________________________________________________________
17
VCC
PWM1
4.7k
Ω
4.7k
Ω
TACH1
3V TO 5.5V
TACH
OUTPUT
VFAN
(5V OR 12V)
Figure 10. 4-Wire Fan with PWM Speed-Control Input
VCC
PWM1
4.7k
Ω
4.7k
Ω
TACH1
3V TO 5.5V
TACH
OUTPUT
VFAN
(12V OR 5V)
5V
Figure 8. High-Side PWM Drive with “Keep-Alive” Supply
VCC
PWM1
TACH1
4.7k
Ω
3V TO 5V
4.7k
Ω
100k
Ω
91k
Ω
33k
Ω
100k
Ω
3.3V
2N3904
2.2
μF
10
μF
TACH
OUTPUT
VFAN
(5V OR 12V)
TACH OUTPUT
Figure 9. High-Side Linear Drive Circuit
相關PDF資料 |
PDF描述 |
|---|---|
| MAX6639FAEE+ | 2-Channel Temperature Monitor with Dual, Automatic, PWM Fan-Speed Controller |
| MAX6640AEE+T | 2-Channel Temperature Monitor with Dual Automatic PWM Fan-Speed Controller |
| MAX6640YAEE+ | 2-Channel Temperature Monitor with Dual Automatic PWM Fan-Speed Controller |
| MAX6640YAEE+T | 2-Channel Temperature Monitor with Dual Automatic PWM Fan-Speed Controller |
| MAX6640AEE+ | 2-Channel Temperature Monitor with Dual Automatic PWM Fan-Speed Controller |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| MAX6639AEE+ | 功能描述:板上安裝溫度傳感器 2Ch Temperature Monitor RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關閉: 安裝風格: 封裝 / 箱體: 設備功能:Temperature and Humidity Sensor |
| MAX6639AEE+T | 功能描述:板上安裝溫度傳感器 2Ch Temperature Monitor RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關閉: 安裝風格: 封裝 / 箱體: 設備功能:Temperature and Humidity Sensor |
| MAX6639AEE-T | 功能描述:馬達/運動/點火控制器和驅動器 RoHS:否 制造商:STMicroelectronics 產品:Stepper Motor Controllers / Drivers 類型:2 Phase Stepper Motor Driver 工作電源電壓:8 V to 45 V 電源電流:0.5 mA 工作溫度:- 25 C to + 125 C 安裝風格:SMD/SMT 封裝 / 箱體:HTSSOP-28 封裝:Tube |
| MAX6639ATE | 功能描述:馬達/運動/點火控制器和驅動器 RoHS:否 制造商:STMicroelectronics 產品:Stepper Motor Controllers / Drivers 類型:2 Phase Stepper Motor Driver 工作電源電壓:8 V to 45 V 電源電流:0.5 mA 工作溫度:- 25 C to + 125 C 安裝風格:SMD/SMT 封裝 / 箱體:HTSSOP-28 封裝:Tube |
| MAX6639ATE+ | 功能描述:板上安裝溫度傳感器 2Ch Temperature Monitor RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關閉: 安裝風格: 封裝 / 箱體: 設備功能:Temperature and Humidity Sensor |
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