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参数资料
| 型号： | NCP1271ADAPGEVB |
| 厂商： | ON Semiconductor |
| 文件页数： | 11/21页 |
| 文件大小： | 0K |
| 描述： | EVAL BOARD FOR NCP1271ADAPG |
| 设计资源： | NCP1271 Adapter EVB BOM NCP1271ADAPGEVB Gerber Files NCP1271EVB 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： | 19V |
| 电流 - 输出： | 3A |
| 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： | NCP1271 |
| 其它名称： | NCP1271ADAPGEVBOS |
NCP1271
cleared after the double hiccup, then the application
restarts. If not, then the process is repeated.
4. Latched Shutdown – When the Skip/latch pin (Pin
1) voltage is pulled above 8.0 V for more than
13 m s, the NCP1271 goes into latchoff shutdown.
The output is held low and V CC stays in hiccup
mode until the latch is reset. The reset can only
occur if Vcc is allowed to fall below V CC(reset)
(4.0 V typical). This is generally accomplished by
unplugging the main input AC source.
5. Non ? Latched Shutdown – If the FB pin is pulled
below the skip level, then the device will enter a
non ? latched shutdown mode. This mode disables
the driver, but the controller automatically recovers
when the pulldown on FB is released. Alternatively,
Vcc can also be pulled low (below 190 mV) to
shutdown the controller. This has the added benefit
of placing the part into a low current consumption
mode for improved power savings.
Biasing the Controller
During startup, the Vcc bias voltage is supplied by the
Startup current
4.1 mA
200 uA
0.6 V V CC(latch) V CC(on) V CC
Figure 23. Startup Current at Various V CC Levels
V CC Double Hiccup Mode
Figure 24 illustrates the block diagram of the startup
circuit. An undervoltage lockout (UVLO) comparator
monitors the V CC supply voltage. If V CC falls below
V CC(off) , then the controller enters “double hiccup mode.”
V bulk
HV
HV Pin (Pin 8). This pin is capable of supporting up to
500 V, so it can be connected directly to the bulk capacitor.
4.1 mA when Vcc > 0.6 V
200 uA when Vcc < 0.6 V
8
Q
S
Internally, the pin connects to a current source which
rapidly charges V CC to its V CC(on) threshold. After this
level is reached, the controller turns on and the transformer
auxiliary winding delivers the bias supply voltage to V CC.
The startup FET is then turned off, allowing the standby
power loss to be minimized. This in ? chip startup circuit
minimizes the number of external components and Printed
Circuit Board (PCB) area. It also provides much lower
power dissipation and faster startup times when compared
to using startup resistors to V CC . The auxiliary winding
needs to be designed to supply a voltage above the V CC(off)
level but below the maximum V CC level of 20 V.
For added protection, the NCP1271 also include a dual
startup mode. Initially, when V CC is below the inhibit
voltage V inhibit (600 mV typical), the startup current source
is small (200 uA typical). The current goes higher (4.1 mA
turn off
UVLO
+
?
R
12.6/
5.8 V
double
hiccup
B 2 9 .1 V
Counter
?
+
&
20V
turn on internal bias
6
Vcc
typical) when V CC goes above V inhibit . This behavior is
illustrated in Figure 23. The dual startup feature protects
the device by limiting the maximum power dissipation
when the V CC pin (Pin 6) is accidentally grounded. This
slightly increases the total time to charge V CC , but it is
generally not noticeable.
Figure 24. V CC Management
During double hiccup operation, the Vcc level falls to
V CC(latch) (5.8 V typical). At this point, the startup FET is
turned back on and charges V CC to V CC(on) (12.6 V typical).
V CC then slowly collapses back to the V CC(latch) level. This
cycle is repeated twice to minimize power dissipation in
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相关代理商/技术参数 |
参数描述 |
|---|---|
| NCP1271ADAPGEVB | 制造商:ON Semiconductor 功能描述:57 W Adapter Eval. Board |
| NCP1271D100R2G | 功能描述:电流型 PWM 控制器 ANA PMW 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 |
| NCP1271D100R2GH | 制造商:Rochester Electronics LLC 功能描述: 制造商:ON Semiconductor 功能描述: |
| NCP1271D65R2G | 功能描述:电流型 PWM 控制器 ANA PMW 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 |
| NCP1271D65R2GH | 制造商:Rochester Electronics LLC 功能描述: 制造商:ON Semiconductor 功能描述: |
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