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参数资料
| 型号： | NCP1012GEVB |
| 厂商： | ON Semiconductor |
| 文件页数： | 15/24页 |
| 文件大小： | 0K |
| 描述： | EVAL BOARD FOR NCP1012G |
| 设计资源： | NCP1012 Eval Brd BOM NCP1012GEVB Gerber Files NCP1012 Eval Brd Schematic |
| 标准包装： | 1 |
| 主要目的： | AC/DC，主面 |
| 输出及类型： | 1，隔离 |
| 输出电压： | 12V |
| 输入电压： | 230VAC |
| 稳压器拓扑结构： | 回扫 |
| 频率 - 开关： | 100kHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | NCP1012 |
| 其它名称： | NCP1012GEVBOS |
NCP1010, NCP1011, NCP1012, NCP1013, NCP1014
Full Latching Shutdown
Other applications require a full latching shutdown, e.g.
when an abnormal situation is detected (overtemperature
or overvoltage). This feature can easily be implemented
through two external transistors wired as a discrete SCR.
When the OVP level exceeds the Zener breakdown
Rhold
voltage, the NPN biases the PNP and fires the equivalent
SCR, permanently bringing down the FB pin. The
switching pulses are disabled until the user unplugs the
power supply.
OVP
10 k
12 k
BAT54
+
CV cc
1
2
3
4
8
7
5
Drain
10 k
Figure 24. Two Bipolars Ensure a Total Latch--Off of the SMPS in Presence of an OVP
Pmax = Jmax
(eq. 12) which gives around
formula: Pmos = 1 · Ip2 · d · RDSon , where Ip
Rhold ensures that the SCR stays on when fired. The bias
current flowing through Rhold should be small enough to let
the V CC ramp up (8.5 V) and down (7.5 V) when the SCR
is fired. The NPN base can also receive a signal from a
temperature sensor. Typical bipolars can be MMBT2222
and MMBT2907 for the discrete latch. The MMBT3946
features two bipolars NPN+PNP in the same package and
could also be used.
Power Dissipation and Heatsinking
The NCP101X welcomes two dissipating terms, the DSS
current--source (when active) and the MOSFET. Thus,
Ptot = P DSS + P MOSFET . When the PDIP--7 package is
surrounded by copper, it becomes possible to drop its
thermal resistance junction--to--ambient, R θ JA down
to 75 ? C/W and thus dissipate more power. The
maximum power the device can thus evacuate is:
T ? Tambmax
R θ JA
1.0 W for an ambient of 50 ? C. The losses inherent to the
MOSFET R DSon can be evaluated using the following
(eq. 13)
3
is the worse case peak current (at the lowest line input), d is
the converter operating duty--cycle and R DSon , the
MOSFET resistance for T J = 100 ? C. This formula is only
valid for Discontinuous Conduction Mode (DCM)
operation where the turn--on losses are null (the primary
current is zero when you restart the MOSFET). Figure 25
gives a possible layout to help drop the thermal resistance.
When measured on a 35 m m (1 oz) copper thickness PCB,
we obtained a thermal resistance of 75 ? C/W.
Figure 25. A Possible PCB Arrangement to Reduce the Thermal Resistance Junction--to--Ambient
http://onsemi.com
15
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相关代理商/技术参数 |
参数描述 |
|---|---|
| NCP1012ST100T3 | 功能描述:电流型 PWM 控制器 Low Standby Power RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| NCP1012ST100T3G | 功能描述:电流型 PWM 控制器 Low Standby Power Monolithic Switcher RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| NCP1012ST130T3 | 功能描述:电流型 PWM 控制器 Low Standby Power RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| NCP1012ST130T3G | 功能描述:电流型 PWM 控制器 Low Standby Power Monolithic Switcher RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| NCP1012ST65T3 | 功能描述:电流型 PWM 控制器 Low Standby Power RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
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