參數(shù)資料
型號(hào)： NCP1381
廠商： ON SEMICONDUCTOR
英文描述： Low−Standby High Performance PWM Controller
文件頁(yè)數(shù)： 9/26頁(yè)
文件大小： 559K
代理商： NCP1381
NCP1381
http://onsemi.com
9
Figure 6.
V
CC
DRV
VCC
ON
VCC
OFF
100 ms
< 100 ms
Bunch Length Given by Timer
Bunch Length Given
by VCC
OFF
If V
CC
drops below VCC
OFF
during a portion where the timer
counts, pulses are immediately stopped and the latchoff phase
is entered. Here, in this example, the timer was set to 100 ms.
QuasiResonance Operation
QuasiResonance (QR) implies that the controller
permanently monitors the transformer core flux activity and
ensures Borderline Conduction Mode (BCM) operation.
That is to say, when the switch closes, the current ramps up
in the magnetizing inductance L
P
until it reaches a setpoint
imposed by the feedback loop. At this point, the power
switch opens and the energy transfers from the primary side
to the secondary (isolated) portion. The secondary diode is
now biased and the output voltage “flies back” to the
primary side, now demagnetizing the primary inductance
L
P
. When this current reaches zero, the transformer core is
said to be “reset” ( = 0). At this time, we can turn the
MOSFET on again to create a new cycle. Figure 7
and 8
portray the typical waveforms with their associated
captions. If a delay TW is introduced further to the core reset
detection and before biasing the power MOSFET, the drain
signal Vds(t) has the time to go through a minimum, also
called valley. Therefore, when we will finally reactivate the
power MOSFET, its draintosource voltage will be
minimum, reducing capacitive losses but also its
gatecharge value, since the Miller effect gets diminished at
low Vds.
Figure 7. Typical QuasiResonance
Waveform
TW
t
OFF
Leakage
Ringing
1st Valley
t
ON
Figure 8. Magnetizing Inductance Current
Waveforms
s
OFF
N
(V
out
V
f
)
L
P
s
ON
V
in
L
P
I
peak
ON
OFF
0
I
P
= 0
TW
The flux activity monitoring is actually made via an
auxiliary winding, obeying the law, V
aux
= N . d / dt.
Figure 9 describes how the detection is made, since the
signal obtained on the auxiliary winding is centered to zero.
Let’s split the events with their associated circuitry:
t
ON
The D flipflop output is high, the MOSFET is enhanced
and current growsup in the primary winding. This is the
on
portion of Figure 8, left side of the triangle. When the driver
output went high, its rising edge triggered a 8 s timer. This
8 s timer provides a true frequency clamp by driving the
Dinput of the flipflop. Now, when the peak current
reaches the level imposed by the feedback loop, a reset
occurs and the flipflop output comes low.
If for any reason the controller keeps the gate high
(DRV
out
) implying a t
ON
longer than 50 s, then all pulses
are stopped and the controller enters a safe, autorecovery,
restart mode. This condition can occur if the current sense
pin does not receive any signal from the sense resistor or if
a shortcircuit brings the CS pin to ground for instance.
相關(guān)PDF資料
PDF描述
NCP1381DR2G Low&#8722;Standby High Performance PWM Controller
NCP1395APG High Performance Resonant Mode Controller
NCP1395ADR2G High Performance Resonant Mode Controller
NCP1395BDR2G High Performance Resonant Mode Controller
NCP1395BPG High Performance Resonant Mode Controller
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
NCP1381 AM90 WAF 制造商:ON Semiconductor 功能描述:
NCP1381ADAPEVB 功能描述:BOARD EVAL NCP1381 RoHS:是 類(lèi)別:編程器，開(kāi)發(fā)系統(tǒng) >> 評(píng)估演示板和套件 系列:* 標(biāo)準(zhǔn)包裝:1 系列:PCI Express® (PCIe) 主要目的:接口，收發(fā)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(kāi)關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)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(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)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(kāi)關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)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(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14
NCP1392B 制造商:ONSEMI 制造商全稱(chēng):ON Semiconductor 功能描述:High-Voltage Half-Bridge Driver with Inbuilt Oscillator
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫(xiě)一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*