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參數資料
| 型號： | NCP1381 |
| 廠商： | ON SEMICONDUCTOR |
| 英文描述： | Low−Standby High Performance PWM Controller |
| 文件頁數： | 7/26頁 |
| 文件大小： | 559K |
| 代理商： | NCP1381 |
NCP1381
http://onsemi.com
7
Startup sequence
When the power supply is first connected to the mains
outlet, the NCP1381 starts to consume current. However,
due to a novel architecture, the internal startup current is
kept very low, below 15 A as a maximum value. The
current delivered by the startup resistor also feeds the V
CC
capacitor and its voltage rises. When the voltage on this
capacitor reaches the VCC
ON
level (typically 15 V), the
controller delivers pulses and increases its consumption. At
this time, the V
CC
capacitor alone supplies the controller: the
auxiliary supply is supposed to take over before V
CC
collapses below VCC
OFF
. Figure 3 shows the internal
arrangement of this structure:
Figure 3. The Startup Resistor Brings V
CC
Above 15 V
8
10
+
I
startup
R
startup
I
total
High Voltage
Auxiliary
Winding
UVLO
VCC
ON
VCC
OFF
+
+
CV
CC
Figure 4. The Timer Section Uses a Current Source
to Charge Up the Capacitor
Reset
+
+
4
10
SoftStart
SoftBurst
I
P
Flag
Fault
Confirmed
V
CC
CV
CC
I
CC3
R
startup
HV
Latchoff
V
CC
Management
+
C
timer
I
timer
V
DD
4.0 V
SW
As soon as V
CC
reaches 15 V (VCC
ON
), driving pulses are
delivered on Pin 9 and the auxiliary winding grows up the
V
CC
pin. Because the output voltage is below the target (the
SMPS is starting up), the controller smoothly pushes the
peak current to I
max
(0.8 V / R
sense
) which is reached after
5 ms (typical internal softstart period). After softstart
completion, the peak current setpoint reaches its maximum
(during the startup period but also anytime a shortcircuit
occurs), an internal error flag is asserted, I
P
Flag, testifying
that the system is pushed to the maximum power (I
P
= I
P
maximum). This flag is used to detect a faulty condition,
where the converter asks for the maximum peak capability
longer than what has been programmed by the designer. The
duration of the faulty condition is actually set up by a
capacitor connected to Pin 4.
Figure 4 shows a portion of this internal arrangement. If
the fault comparator acknowledges for a problem, the
controller stops all driving pulses and turnson the internal
I
CC3
currentsource. This source serves for the latchoff
phase creation, that is to say, forcing the V
CC
to go down,
despite the presence of the startup current still flowing via
the startup resistor. Therefore, I
CC3
should be greater than
I
total
to ensure proper operation. When V
CC
reaches a level
of 7 V, I
CC3
turns to zero and the startup current can lift V
CC
up again. When V
CC
reaches 15 V, a new attempt is made.
If the fault is still there, pulses last either the timer duration
or are prematurely stopped if a VCC
OFF
condition occurs
sooner, and a new latchoff phase takes place. If the fault has
gone, the converter resumes operation. Figure 5 portrays the
waveforms obtained during a startup sequence followed by
a fault. One can see the action of the I
CC3
source which
creates the latchoff phase and the various resets events on the
timer capacitor in presence of the softstart end or an aborted
fault sequence.
Knowing that I
timer
equals 10 A, we can calculate the
capacitor needed to reach 4 V in a typical time period.
Suppose we would like a 100 ms fault duration, therefore:
C
timer
= 10 x 100 m / 4 = 250 nF, select a 0.22 F.
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相關代理商/技術參數 |
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| NCP1381 AM90 WAF | 制造商:ON Semiconductor 功能描述: |
| NCP1381ADAPEVB | 功能描述:BOARD EVAL NCP1381 RoHS:是 類別:編程器，開發系統 >> 評估演示板和套件 系列:* 標準包裝:1 系列:PCI Express® (PCIe) 主要目的:接口，收發器，PCI Express 嵌入式:- 已用 IC / 零件:DS80PCI800 主要屬性:- 次要屬性:- 已供物品:板 |
| NCP1381DR2G | 功能描述:電流型 PWM 控制器 ANA PWM CONTROLLER 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 |
| NCP1382DR2G | 功能描述:電流型 PWM 控制器 L-STNDBY PWM CNTRLR 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 |
| NCP1392B | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:High-Voltage Half-Bridge Driver with Inbuilt Oscillator |
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