- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄67801 > MAX6651EEE+T (MAXIM INTEGRATED PRODUCTS INC) Fan-Speed Regulators and Monitors with SMBus™/I<sup>2</sup>C-Compatible Interface PDF資料下載
參數(shù)資料
| 型號： | MAX6651EEE+T |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 運(yùn)動控制電子 |
| 英文描述： | Fan-Speed Regulators and Monitors with SMBus™/I<sup>2</sup>C-Compatible Interface |
| 中文描述： | BRUSHLESS DC MOTOR CONTROLLER, 0.1 A, PDSO16 |
| 封裝： | QSOP-16 |
| 文件頁數(shù)： | 15/25頁 |
| 文件大?。?/td> | 315K |
| 代理商： | MAX6651EEE+T |
MAX6650/MAX6651
We will start with KSCALE = 2 (to increase stability, a 4
could be tried, or to improve response time, a 1 could
be tried).
Second, calculate the appropriate value for the Speed
Register (KTACH) using equation 2.
Set FanSpeed = 25RPS (1500PRM/60).
Solving for equation 2 gives KTACH = 78 for KSCALE
= 2, KTACH = 39 for KSCALE = 1, or KTACH = 158 for
K = 4.
Determining the Tachometer Count Time
To monitor the fan speed using the SMBus/I2C, the next
step is to determine the tachometer count time. In sys-
tems running in open-loop mode, this is necessary. In
closed-loop or full-speed mode, reading the tachome-
ter can serve as a valuable check to ensure the fan and
the control loop are operating properly.
The MAX6650/MAX6651 use an 8-bit counter to count
the tachometer pulses. This means the device can
count from 0 to 255 tachometer pulses before overflow-
ing. The MAX6650/MAX6651 can accommodate a large
range of fan speeds by allowing the counting interval to
be programmed. Smaller/faster fans should use smaller
count times. Although larger fans could also use small-
er count times, resolution would suffer. Choose the
slowest count time that will not overflow under worst-
case conditions. Fans are mechanical devices, and
their speeds are subject to large tolerance variations. If
an overflow does occur, the counter will read 255. The
MAX6650/MAX6651 can be configured to generate an
alert if an overflow is encountered (see Setting Up
Alarms). Note that the prescaler value has no effect on
the TACH0 register.
Enter the appropriate count-time value in the tachometer
count-time register.
Example:
Assume a 12V fan rated at 2000 RPM.
To accommodate large tolerance variations, choose a
count time appropriate for a maximum speed of
3000RPM; 3000RPM is 50RPS and generates a 100Hz
(2 pulses/revolution) tachometer signal. Table 9 indi-
cates a count time of 2s will optimize resolution. With a
2s count time, speeds as fast as 3825RPM can be
monitored without overflow. The minimum resolution will
be 15RPM or 0.75% of the rated speed of 2000RPM.
Setting Up the GPIOs
To increase versatility, the MAX6650/MAX6651 have
two and five general-purpose digital inputs/outputs,
respectively. These GPIOs can be configured through
the SMBus/I2C.
Digital Out Low
All GPIOs can be configured to output a logic-level low.
The MAX6650/MAX6651 are designed to sink up to
10mA. This high sink current can be especially useful
for driving LEDs.
For GPIO3 and GPIO4, write a zero to the appropriate
location in the GPIO definition register.
For GPIO0, GPIO1, and GPIO2, write a 10 to the appro-
priate location in the GPIO definition register.
Digital Out High
All GPIOs can be configured to generate a logic-level
high. An output high is generated using an open-drain
output stage with an internal pullup resistor of nominally
100k
. The MAX6650/MAX6651 power-up default state
is with all GPIOs configured as output highs.
For GPIO3 and GPIO4, write a 1 to the appropriate
location in the GPIO definition register.
For GPIO0, GPIO1, and GPIO2, write an 11 to the
appropriate location in the GPIO definition register.
Digital Input
Since a logic-level high output is open drain with an
internal pullup, an external device can actively pull this
pin low. The MAX6650/MAX6651 allow the user to read
the GPIO value through the GPIO status register.
Configure the GPIO as an output logic level high (see
above).
Read the state of the GPIO by reading the GPIO sta-
tus register.
Alert Output
GPIO0 can also serve as an ALERT output. The ALERT
output is designed to drive an interrupt on a C. The
ALERT output goes low whenever an enabled alarm
condition occurs (see Setting Up Alarms).
Configure GPIO0 as an ALERT output by writing a 01 to
bits 1 and 0 of the GPIO definition register.
Full-On Input
GPIO1 can also be configured as a full-on input. When
the full-on pin is pulled low, the MAX6650/MAX6651
apply the full available voltage across the fan. This hap-
pens independently of the software mode of operation.
This is a particularly valuable feature in high-reliability
systems, designed to prevent software malfunctions
from causing system overheating.
Configure GPIO1 as a full-on input by writing a 01 to
bits 3 and 2 of the GPIO definition register.
Fan-Speed Regulators and Monitors
with SMBus/I2C-Compatible Interface
22
______________________________________________________________________________________
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MAX6650EUB+ | Fan-Speed Regulators and Monitors with SMBus™/I<sup>2</sup>C-Compatible Interface |
| MAX6651EEE+ | Fan-Speed Regulators and Monitors with SMBus™/I<sup>2</sup>C-Compatible Interface |
| MAX6652AUB+ | Temperature Sensor and System Monitor in a 10-Pin µMAX |
| MAX6652AUB+T | Temperature Sensor and System Monitor in a 10-Pin µMAX |
| MAX6654MEE+ | 1°C Accurate Remote/Local Temperature Sensor with SMBus Serial Interface |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX6651EVCMAXQU | 功能描述:電源管理模塊 MAX6651 Evaluation Kit/Evaluation System RoHS:否 制造商:ROHM Semiconductor 產(chǎn)品:AC-DC Converters 最大輸入電壓:264 VAC 開關(guān)頻率: 輸出電壓:10 V to 28.8 V 輸出電流:350mA 負(fù)載調(diào)節(jié): 最大工作溫度:+ 60 C 尺寸:100 mm x 16 mm x 17 mm |
| MAX6651EVKIT | 功能描述:電源管理IC開發(fā)工具 RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
| MAX6651EVSYS | 功能描述:電源管理IC開發(fā)工具 RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
| MAX6652AUB | 功能描述:板上安裝溫度傳感器 RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準(zhǔn)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(guān)閉: 安裝風(fēng)格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| MAX6652AUB+ | 功能描述:板上安裝溫度傳感器 Temperature Sensor & System Monitor RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準(zhǔn)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(guān)閉: 安裝風(fēng)格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。