参数资料
| 型号： | NCP4302BDR2G |
| 厂商： | ON Semiconductor |
| 文件页数： | 11/16页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR FLYBK ISO PWM 8SOIC |
| 标准包装： | 1 |
| PWM 型： | 控制器 |
| 输出数： | 1 |
| 频率 - 最大： | 250kHz |
| 电源电压： | 9.2 V ~ 28 V |
| 降压： | 无 |
| 升压： | 无 |
| 回扫： | 是 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 是 |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 包装： | 剪切带 (CT) |
| 其它名称： | NCP4302BDR2GOSCT |
NCP4302
Detailed Operating Description
The NCP4302 is designed to operate either as a standalone
IC or as a companion IC to a primary side controller to help
achieve efficient synchronous rectification for flyback
converter systems. It has high current gate driver along with
fast logic circuitry to provide appropriately timed drive
signals to a synchronous MOSFET used for output
rectification in a flyback converter. With its novel
architecture, the NCP4302 has enough versatility to increase
the synchronous rectification efficiency under any operating
mode without requiring too much complexity.
Supply Section
The NCP4302 works from an available bias supply that
can range from 10.4 V to 28 V (typical). This allows direct
connection to the output voltage of many adapters such as
notebook and LCD TV adapters. As a result, the NCP4302
simplifies circuit operation compared to other devices
which require specific bias power supplies (e.g. 5 V). The
high voltage capability of the V CC is also a unique feature
designed to allow operation across a broader range of
applications. To prevent gate signal from operating under
SYNC/CS Input
In a synchronous rectification application after the
primary side MOSFET is turned ? off, the current in the
secondary of the flyback transformer initially flows through
the synchronous rectification MOSFET’s internal body
diode. When this occurs, the drain of the MOSFET will be
? 0.5 to ? 1.0 V negative with respect to ground (the VF of the
internal body diode) and the NCP4302 current sense
differential amplifier will output a 230 m A current (typical).
This current detection method is used by the NCP4302 to
determine when current is flowing in the secondary of the
transformer and the Synchronous Rectification MOSFET
needs to be turned ? on.
The zero current detection senses the current with a slight
negative offset so that the switch turn ? off occurs without
reversal of the current.
Cout Vout
Current Sense Amplifier
inadequate bias conditions, the NCP4302 features a UVLO
circuit that turns on at 10.4 V (V CC rising) typical and turns
off at 9.2 V typical (V CC falling).
75
Mirror
To Reset
Dominant
Flip ? Flop
Gate Drive Section
The NCP4302 features high current gate drivers
delivering up to (>2.5 A peak) to achieve fast turn ? on and
turn ? off requirements in a synchronous rectifier. Having a
high gate drive current enables fast turn ? on when SYNC/CS
signal is received (to minimize body diode conduction at the
peak of the current waveform) and fast turn ? off when zero
current or a TRIG signals are received (to prevent current
reversal or cross conduction). The higher sink current also
allows the MOSFET to be kept off during the instances when
there is high dv/dt on the drain.
The gate voltage is clamped at 13.5 V typical to prevent
larger excursion of gate voltage than needed when V CC is
operating from a 28 Vdc output.
The propagation delays through the logic circuits and the
gate drivers are kept at a minimum as shown in the
specification table.
45.0 V
37.5 V
25.0 V
12.5 V
0V
Figure 25. Input Current Sense
Adjustable t on Delay
The SYNC/CS input to the NCP4302 is used as a Reset
(through logic) input to the drive enable Flip Flop; refer to
the internal block diagram of the NCP4302. When current
flows in the secondary of the Flyback transformer any
parasitic inductance due to printed wiring board traces, or
component lead can cause the voltage at the SYNC/CS input
to ring above ground (refer to Figure 26). This ringing may
cause the controller dive output to turn ? off. To eliminate this
problem the NCP4302 has a programmable t on time which
blanks the secondary voltage ringing by adding a minimum
controller drive on time.
V(U1:4)
60 m s
70 m s
80 m s
90 m s
100 m s
110 m s
120 m s
Time
Figure 26. Discontinuous Conduction Mode Drain Waveform
http://onsemi.com
11
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相关代理商/技术参数 |
参数描述 |
|---|---|
| NCP4303A | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Secondary Side Synchronous Rectification Driver for High Efficiency SMPS Topologies |
| NCP4303ADR2G | 功能描述:初级与次级侧 PWM 控制器 SEC SIDE SYNC RECT DRV RoHS:否 制造商:ON Semiconductor 输出端数量:1 开关频率:250 KHz 工作电源电压:- 0.3 V to + 28 V 最大工作温度:+ 85 C 最小工作温度:- 5 C 封装 / 箱体:SOIC-8 Narrow 封装:Reel |
| NCP4303AMNTWG | 功能描述:IC CTLR/DVR SYNC RECT 8-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电源控制器，监视器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 应用:多相控制器 输入电压:- 电源电压:9 V ~ 14 V 电流 - 电源:- 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:40-WFQFN 裸露焊盘 供应商设备封装:40-TQFN-EP（5x5） 包装:带卷 (TR) |
| NCP4303B | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Secondary Side Synchronous Rectification Driver for High Efficiency SMPS Topologies |
| NCP4303BDR2G | 功能描述:初级与次级侧 PWM 控制器 SEC SIDE SYNC RECT DRV RoHS:否 制造商:ON Semiconductor 输出端数量:1 开关频率:250 KHz 工作电源电压:- 0.3 V to + 28 V 最大工作温度:+ 85 C 最小工作温度:- 5 C 封装 / 箱体:SOIC-8 Narrow 封装:Reel |
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