- 您現在的位置：買賣IC網 > PDF目錄375914 > FS6X1220R (Fairchild Semiconductor Corporation) Fairchild Power Switch (FPS) PDF資料下載
參數資料
| 型號： | FS6X1220R |
| 廠商： | Fairchild Semiconductor Corporation |
| 英文描述： | Fairchild Power Switch (FPS) |
| 中文描述： | 飛兆半導體功率開關（FPS） |
| 文件頁數： | 9/16頁 |
| 文件大小： | 471K |
| 代理商： | FS6X1220R |
FS6X1220R
9
3.2 Over Load Protection (OLP)
: Overload means that the
load current exceeds a pre-set level due to an abnormal
situation. In this situation, protection circuit should be
activated in order to protect the SMPS. However, even when
the SMPS is in the normal operation, the over load protection
circuit can be activated during the load transition. In order to
avoid this undesired operation, the over load protection
circuit is designed to be activated after a specified period to
determine whether it is a transient situation or an overload
situation. Because of the pulse-by-pulse current limit
capability, the maximum peak current through the SMPS is
limited, and therefore the maximum input power is restricted
with a given input voltage. If the output consumes beyond
this maximum power, the output voltage (Vo) decreases
below the set voltage. This reduces the current through the
opto-coupler diode, which also reduces opto-coupler
transistor current increasing Vfb. If Vfb exceeds 2.6V, D1 is
blocked and the 5
μ
A current source starts to charge Cfb
slowly compared to when the 0.9mA current source charges
Cfb. In this condition, Vfb continues increasing until it
reaches 7.5V, and the switching operation is terminated at
that time as shown in figure 4. The delay time for shutdown
is the time required to charge Cfb from 2.6V to 7.5V with
5
μ
A. When Cfb is 10nF (103), T
12
is approximately 9.8ms
and when Cfb is 0.1
μ
F (104), T
12
is approximately 98ms.
These values are enough to prevent SMPS from being shut
down during transient situations.
Figure 4. Over load protection
3.3 Over voltage Protection (OVP)
: In case of malfunction
in the secondary side feedback circuit, or feedback loop open
caused by a defect of solder, the current through the opto-
coupler transistor becomes almost zero. Then, Vfb climbs up
in a similar manner to the over load situation, forcing the
preset maximum current to be supplied to the secondary side
until the over load protection is activated. Because energy
more than required is provided to the output, the output
voltage may exceed the rated voltage before the over load
protection is activated, resulting in the breakdown of the
devices in the secondary side. In order to prevent this
situation, an over voltage protection (OVP) circuit is
employed. In general, Vcc is proportional to the output
voltage and FS6X1220R uses Vcc instead of directly
monitoring the output voltage. If V
CC
exceeds 25V, OVP
circuit is activated resulting in termination of switching. In
order to avoid undesired activation of OVP during normal
operation, Vcc should be properly designed to be below 25V.
3.4 Thermal Shutdown (TSD)
: The thermal shutdown
circuitry senses the junction temperature. The threshold is set
at 160
°
C.
When the junction temperature rises above this
threshold (160
°
C
) the power MOSFET is disabled.
4. The Line UVLO and Sleep Mode
According to the voltage of Line Sense pin, three operation
modes are defined; Normal operation mode, Line under
voltage lock out mode and Sleep mode as shown in figure 5.
When the voltage of this pin is over 2.55V, FS6X1220R
operates in normal mode. When the voltage of this pin is
smaller than 2.55V, it goes into line under voltage lock out
mode terminating switching operation. When the voltage of
this pin is smaller than 1.8V, it enters into sleep mode.
During sleep mode, reference voltage generation circuit
including shunt regulator is disabled and only 300
μ
A
operation current is required.
Figure 5. Line Sense block
V
FB
t
2.6V
7.5V
Over load protection
T
12
= Cfb*(7.5-2.6)/I
delay
T
1
T
2
V
(1.8v)
V
(2.5V)
9V/15V
3
5
Vref
Line UVLO
Enable
Internal
Bias
Vcc good
Line
Sense
Vcc
Vin
R1
R2
Sleep
ON OFF
相關PDF資料 |
PDF描述 |
|---|---|
| FS6X1220RD | Fairchild Power Switch (FPS) |
| FS6X1220RTYDTU | Fairchild Power Switch (FPS) |
| FS70KM-06 | CAP 0.01UF 50V 10% NP0(C0G) AXIAL RAD.20 BULK M-MIL-PRF-20 STANDOFF |
| FS70KM-06 | CAP 1500PF 200V 1% NP0(C0G) AXIAL RAD.20 BULK S-MIL-PRF-20 STANDOFF |
| FS70KM-2 | CAP 0.1UF 50V 2% NP0(C0G) AXIAL RAD.40 BULK R-MIL-PRF-20 |
相關代理商/技術參數 |
參數描述 |
|---|---|
| FS6X1220R_05 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Fairchild Power Switch (FPS) |
| FS6X1220RD | 功能描述:電源開關 IC - 配電 12A/200V DC/DC Off-line PS RoHS:否 制造商:Exar 輸出端數量:1 開啟電阻（最大值）:85 mOhms 開啟時間（最大值）:400 us 關閉時間（最大值）:20 us 工作電源電壓:3.2 V to 6.5 V 電源電流（最大值）: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOT-23-5 |
| FS6X1220RJ | 功能描述:電流型 PWM 控制器 12A/200V DC/DC Off-line Power Sw RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| FS6X1220RJX | 功能描述:電流型 PWM 控制器 POWER_CONVERSION RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| FS6X1220RTTU | 功能描述:電源開關 IC - 配電 RoHS:否 制造商:Exar 輸出端數量:1 開啟電阻（最大值）:85 mOhms 開啟時間（最大值）:400 us 關閉時間（最大值）:20 us 工作電源電壓:3.2 V to 6.5 V 電源電流（最大值）: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOT-23-5 |
發(fā)布緊急采購，3分鐘左右您將得到回復。