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参数资料
| 型号： | TC642 |
| 厂商： | Microchip Technology Inc. |
| 英文描述： | PWM Fan Speed Controller with FanSense⑩ Technology |
| 中文描述： | 与FanSense PWM风扇速度控制器⑩技术 |
| 文件页数： | 5/28页 |
| 文件大小： | 485K |
| 代理商： | TC642 |
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2002 Microchip Technology Inc.
DS21444C-page 5
TC642
3.0
DETAILED DESCRIPTION
3.1
PWM
The PWM circuit consists of a ramp generator and
threshold detector. The frequency of the PWM is deter-
mined by the value of the capacitor connected to the C
F
input. A frequency of 30 Hz is recommended
(C
F
= 1 μF). The PWM is also the time base for the
Start-up Timer (see Section 3.4, “Start-Up Timer”). The
PWM voltage control range is 1.25V to 2.65V (typical)
for 0% to 100% output duty cycle.
3.2
FAULT Output
The TC642 detects faults in two ways.
First, pulses appearing at SENSE due to the PWM
turning on are blanked, with the remaining pulses
filtered by a missing pulse detector. If consecutive
pulses are not detected for 32 PWM cycles (
1 Sec if
C
F
= 1 μF), the Diagnostic Timer is activated, and V
OUT
is driven high continuously for three PWM cycles
(
100 msec if C
F
= 1 μF). If a pulse is not detected
within this window, the Start-up Timer is triggered (see
Section 3.4). This should clear a transient fault condi-
tion. If the missing pulse detector times out again, the
PWM is stopped and FAULT goes low. When FAULT is
activated due to this condition, the device is latched in
shutdown mode and will remain off indefinitely.
The TC642 may be configured to continuously attempt
fan restarts, if so desired.
Continuous restart mode is enabled by connecting the
FAULT output to V
MIN
through a 0.01 μF capacitor, as
shown in Figure 3-1. When connected in this manner,
the TC642 automatically attempts to restart the fan
every time a fault condition occurs. When the FAULT
output is driven low, the V
MIN
input is momentarily
pulled below V
SHDN
, initiating a reset and clearing the
fault condition. Normal fan start-up is then attempted as
previously described. The FAULT output may be
connected to external logic (or the interrupt input of a
microcontroller) to shut the TC642 down if multiple fault
pulses are detected at approximately one second
intervals. Diode D
1
, capacitor C
1
and resistors R
5
and
R
6
are provided to ensure fan restarts are the result of
a fan fault and not an over-temperature fault. A CMOS
logic OR gate may be substituted for these
components, if available.
FIGURE 3-1:
Fan Fault Output Circuit.
Note:
At this point, action
must
be taken to restart
the fan by momentarily pulling V
MIN
below
V
SHDN
, or cycling system power. In either
case, the fan
cannot
remain disabled due
to a fault condition, as severe system dam-
age could result. If the fan cannot be
restarted, the system should be shut down.
FAULT
SENSE
R
3
R
1
R
5
10k
D
1
R
4
GND
From
System
Shutdown
Controller
(Optional)
*The parallel combination of R
3
and R
4
must be >10 k
.
Q
1
+12V
+5V
V
DD
V
IN
V
MIN
V
OUT
R
BASE
R
6
1k
V
DD
R
SENSE
C
SENSE
C
F
1
μ
F
C
F
TC642
Fan
C
0.01
μ
F
1
8
6
7
5
4
2
3
From
Temp
Sensor
+5V
0.01
μ
F
1
0
TC642
RESET
Fault
Detected
C
1
Q
2
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相关代理商/技术参数 |
参数描述 |
|---|---|
| TC642_13 | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:PWM Fan Speed Controller with FanSensea?￠ Technology |
| TC642B | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:PWM Fan Speed Controllers With Minimum Fan Speed, Fan Restart and FanSense⑩ Technology for Fault Detection |
| TC642B_13 | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:PWM Fan Speed Controllers With Minimum Fan Speed, Fan Restart and FanSensea?￠ Technology for Fault Detection |
| TC642BEOA | 功能描述:马达/运动/点火控制器和驱动器 w/Rstrt & Flt Dtct 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 |
| TC642BEOA713 | 功能描述:马达/运动/点火控制器和驱动器 w/Rstrt & Flt Dtct 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 |
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