參數(shù)資料
型號： NCP1207A
廠商： ON SEMICONDUCTOR
英文描述： PWM Current Mode Controller for Free Running Quasi Resonant Operation(電流模式控制的PWM控制器，用于自由振蕩的“準諧振”操作)
中文描述： PWM電流模式控制器運行準諧振操作（電流模式控制的脈寬調(diào)制控制器，用于自由振蕩的“準諧振”操作免費）
文件頁數(shù)： 7/16頁
文件大?。?/td> 239K
代理商： NCP1207A
NCP1207A
http://onsemi.com
7
APPLICATION INFORMATION
Introduction
The NCP1207A implements a standard current mode
architecture where the switchoff time is dictated by the
peak current setpoint whereas the core reset detection
triggers the turnon event. This component represents the
ideal candidate where low partcount is the key parameter,
particularly in lowcost AC/DC adapters, consumer
electronics, auxiliary supplies, etc. Thanks to its
highperformance
HighVoltage
NCP1207A incorporates all the necessary components /
features needed to build a rugged and reliable SwitchMode
Power Supply (SMPS):
Transformer core reset detection:
borderline / critical
operation is ensured whatever the operating conditions
are. As a result, there are virtually no primary switch
turnon losses and no secondary diode recovery losses.
The converter also stays a firstorder system and
accordingly eases the feedback loop design.
Quasiresonant operation:
by delaying the turnon
event, it is possible to restart the MOSFET in the
minimum of the drainsource wave, ensuring reduced
EMI / video noise perturbations. In nominal power
conditions, the NCP1207A operates in Borderline
Conduction Mode (BCM) also called Critical
Conduction Mode.
Dynamic SelfSupply (DSS):
due to its Very High
Voltage Integrated Circuit (VHVIC) technology,
ON Semiconductor’s NCP1207A allows for a direct pin
connection to the highvoltage DC rail. A dynamic
current source charges up a capacitor and thus provides
a fully independent V
CC
level to the NCP1207A. As a
result, there is no need for an auxiliary winding whose
management is always a problem in variable output
voltage designs (e.g. battery chargers).
Overvoltage Protection (OVP):
by sampling the plateau
voltage on the demagnetization winding, the
NCP1207A goes into latched fault condition whenever
an overvoltage condition is detected. The controller
stays fully latched in this position until the V
CC
is
cycled down 4.0 V, e.g. when the user unplugs the
power supply from the mains outlet and replugs it.
External latch trip point:
by externally forcing a level
on the OVP greater than the internal setpoint, it is
possible to latchoff the IC, e.g. with a signal coming
from a temperature sensor.
Adjustable skip cycle level:
by offering the ability to
tailor the level at which the skip cycle takes place, the
designer can make sure that the skip operation only
technology,
the
occurs at low peak current. This point guarantees a
noisefree operation with cheap transformer. This
option also offers the ability to fix the maximum
switching frequency when entering light load
conditions.
Overcurrent Protection (OCP):
by continuously
monitoring the FB line activity, NCP1207A enters burst
mode as soon as the power supply undergoes an
overload. The device enters a safe low power operation
which prevents from any lethal thermal runaway. As
soon as the default disappears, the power supply
resumes operation. Unlike other controllers, overload
detection is performed independently of any auxiliary
winding level. In presence of a bad coupling between
both power and auxiliary windings, the short circuit
detection can be severely affected. The DSS naturally
shields you against these troubles.
Dynamic SelfSupply
The DSS principle is based on the charge/discharge of the
V
CC
bulk capacitor from a low level up to a higher level. We
can easily describe the current source operation with some
simple logical equations:
POWERON: IF V
CC
< VCC
OFF
THEN Current Source
is ON, no output pulses
IF V
CC
decreasing > VCC
ON
THEN Current Source is
OFF, output is pulsing
IF V
CC
increasing < VCC
OFF
THEN Current Source is
ON, output is pulsing
Typical values are: VCC
OFF
= 12 V, VCC
ON
= 10 V
To better understand the operational principle, Figure 12’s
sketch offers the necessary light.
Figure 12. The Charge/Discharge Cycle Over a 10 F
V
CC
Capacitor
V
C
C
S
V
RIPPLE
= 2 V
ON
OFF
VCC
OFF
= 12 V
VCC
ON
= 10 V
Output Pulses
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
NCP1207A_06 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:PWM Current−Mode Controller for Free Running Quasi−Resonant Operation
NCP1207A_07 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:PWM Current-Mode Controller for Free Running Quasi-Resonant Operation
NCP1207A_10 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:PWM Current--Mode Controller for Free Running Quasi--Resonant Operation
NCP1207AADAPGEVB 功能描述:電源管理IC開發(fā)工具 NCP1207A 24 W RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V
NCP1207ADR2 功能描述:電流型 PWM 控制器 Quasi Resonant RoHS:否 制造商:Texas Instruments 開關(guān)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(shù)量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14
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