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参数资料
| 型号： | TC670ECH |
| 元件分类： | 模拟信号调理 |
| 英文描述： | SPECIALTY ANALOG CIRCUIT, PDSO6 |
| 封装： | EIAJ, SC-74, SOT-23, 6 PIN |
| 文件页数： | 8/12页 |
| 文件大小： | 469K |
| 代理商： | TC670ECH |
2002 Microchip Technology Inc.
DS21688B-page 5
TC670
4.0
DETAILED DESCRIPTION
The TC670 is an integrated fan speed sensor that
predicts/detects fan failure, consequently preventing
thermal damage to systems with cooling fans. When
the fan speed falls below a user programmed threshold
level, the TC670 asserts an ALERT signal. This
threshold is set with an external resistor divider
network.
FIGURE 4-1:
TC670 BLOCK DIAGRAM
As shown in Figure 4-1, the TC670 senses the fan
pulses and internally converts those pulses from a
frequency into an analog voltage. This voltage is then
compared with a DC voltage present on the THRESH-
OLD pin. If the converted frequency-to-voltage value
from the fan’s pulses falls below the THRESHOLD
voltage, a FAULT signal is asserted through the ALERT
pin (active LOW).
In a 3.0V system, the external fan alert level on the
THRESHOLD pin can be designed from 0.0V (stalled
fan) and up to 2.4V (for 13,000 RPM) to cover most of
the common fan speeds. This failure detection system
works with linear controlled 2-wire fans and eliminates
the need for 3-wire fans. The TC670 can work with 3-
wire fans as well either by using the SENSE circuit or
by directly sensing the RPM output from the 3rd wire.
A CLEAR pin is provided to allow the user to reset the
ALERT pin status back to a HIGH state. This CLEAR
option also allows the flexibility of connecting the
ALERT output of the TC670 with other Alert/FAULT
interrupts in the system without having a risk of a
system shutdown due to false Fan Fault condition.
FIGURE 4-2:
TYPICAL APPLICATION
CIRCUIT
4.1
SENSE Input
As shown in Figure 4-2, the SENSE input (Pin 6) is
connected through a sensing capacitor (CSENSE). A
low value current sensing resistor (RSENSE)is also
connected to the low side of the fan to the ground return
leg of the fan. During normal fan operation, commuta-
tion occurs as each pole of the fan is energized. This
causes brief interruptions in the fan current, seen as
pulses across the sense resistor.
These short rapid changes in fan current cause a
corresponding dV/dt voltage across the sense resistor
as well as a corresponding dI/dt current across the
sense capacitor. The current across CSENSE is termi-
nated with the internal 50k
input resistance at the
SENSE pin of the TC670. When positive going fan
pulses at the SENSE input are greater than 124mV
(typ) the TC670 latches in those voltage spikes. This
124mV (typ) SENSE input built-in threshold reduces
false triggering errors caused by extraneous noise
pulses associated with a running fan. The presence
and frequency of these pulses is a direct indication of
fan operation and fan speed.
THRESHOLD
124mV
50k
SENSE
ALERT
CLEAR
Logic
Frequency to
Voltage
GND
VDD
Bandgap
Oscillator
From
Microcontroller
5
6
CSENSE
R4
RSENSE
+12V
ALERT
LED
DC
FAN
DC
FAN
SENSE
ALERT
2
4
3
1
VDD =+5V
R3
R2
0.1 F
VDD
CLEAR
THRESHOLD
GND
Vthreshold
V
TH RESHO LD
V
DD
R
2
R
2
R
3
+
----------------------
=
Note: This typical application circuit uses an LED to indicate that a
fan failure has occurred.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| TC670ECHTR | 功能描述:马达/运动/点火控制器和驱动器 Predictive Fan Failure Det 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 |
| TC670ECHTR | 制造商:Microchip Technology Inc 功能描述:IC CONTROLLER FAN MANAGEMENT 制造商:Microchip Technology Inc 功能描述:IC, CONTROLLER, FAN MANAGEMENT |
| TC670ECHTR | 制造商:Microchip Technology Inc 功能描述:Fan Management Controller IC Package/Cas |
| TC670ECHTR-CUT TAPE | 制造商:Microchip 功能描述:TC670 Series 3 to 5.5 V Tiny Predictive Fan Failure Detector - SOT-23-6 |
| TC68 | 功能描述:铝质电解电容器 - 带引线 60uF 350V RoHS:否 制造商:Kemet 引线类型: 电容:220 uF 容差:20 % 电压额定值:25 V 工作温度范围: 端接类型:Radial 外壳直径:8 mm 外壳长度:11 mm 引线间隔:5 mm 产品:General Purpose Electrolytic Capacitors 封装:Bulk |
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