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| 型号： | NCP1027ATXGEVB |
| 厂商： | ON Semiconductor |
| 文件页数： | 11/30页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL NCP1027 10W STANDBY |
| 设计资源： | NCP1027ATXGEVB Schematic NCP1027ATXGEVB Test Procedure NCP1027ATXGEVB Bill of Materials |
| 标准包装： | 1 |
| 主要目的： | AC/DC，主面 |
| 输出及类型： | 1，非隔离 |
| 功率 - 输出： | 10W |
| 输出电压： | 5V |
| 电流 - 输出： | 2A |
| 输入电压： | 85 ~ 265VAC |
| 稳压器拓扑结构： | 回扫 |
| 频率 - 开关： | 65kHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | NCP1027 |
| 其它名称： | NCP1027ATXGEVB-ND NCP1027ATXGEVBOS |
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NCP1027
Startup Sequence
The NCP1027 includes a high-voltage startup circuitry,
directly deriving current from the bulk line to charge the
Vbulk
I1
RV CC
V CC capacitor. Figure 24 details the simplified internal
arrangement.
+
1
ICC1
IC1
←
5
I2
I clamp
-
+
+
CV CC
Vz = 8.7 V
V CCon
V CCoff
+
I clamp > 6 mA
→ OVP fault
8
Figure 24. Internal Arrangement of the Startup Circuitry
When the power supply is first connected to the mains
outlet, the internal current source is biased and charges up
the V CC capacitor. When the voltage on this V CC capacitor
reaches the VCC ON level (typically 8.5 V), the current
source turns off, reducing the amount of power being
dissipated. At this time, the V CC capacitor only supplies the
controller, and the auxiliary supply should take over before
V CC collapses below VCC (min) . This V CC capacitor, CV CC ,
must therefore be calculated to hold enough energy so that
V CC stays above VCC (min) (7.3 V typical) until the
auxiliary voltage fully takes over.
An auxiliary winding is needed to maintain the V CC in
order to self-supply the switcher. The V CC capacitor has
only a supply role and its value does not impact other
parameters such as fault duration or the frequency sweep
period for instance. As one can see in Figure 24, an internal
active Zener diode, protects the switcher against lethal V CC
runaways. This situation can occur if the feedback loop
optocoupler fails, for instance, and you would like to
protect the converter against an over voltage event. In that
case, the internal current increase incurred by the V CC
rapid growth triggers the over voltage protection (OVP)
circuit and immediately stops the output pulses for 440 ms.
Then a new startup attempt takes place to check whether
the fault has disappeared or not. The OVP paragraph gives
more design details on this particular section.
The V CC capacitor can be calculated knowing a) the
amount of energy that needs to be stored; b) the time it
takes for the auxiliary voltage to appear, and; c) the current
consumed by the controller at that time. For a better
understanding, Figure 25 shows how the voltage evolves
on the V CC capacitor upon startup.
http://onsemi.com
11
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相关代理商/技术参数 |
参数描述 |
|---|---|
| NCP1027P065G | 功能描述:电流型 PWM 控制器 PWM Current Mode Controller 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 |
| NCP1027P100G | 功能描述:交流/直流开关转换器 PWM Current Mode Controller RoHS:否 制造商:STMicroelectronics 输出电压:800 V 输入/电源电压（最大值）:23.5 V 输入/电源电压（最小值）:11.5 V 开关频率:115 kHz 电源电流:1.6 mA 工作温度范围:- 40 C to + 150 C 安装风格:SMD/SMT 封装 / 箱体:SSO-10 封装:Reel |
| NCP1027PO65G | 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:ON Semiconductor 功能描述: |
| NCP1028 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Power Factor Controllers |
| NCP1028LEDGEVB | 功能描述:电源管理IC开发工具 720MA 18V LED DRIVER RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
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