参数资料
| 型号： | NCP1378PG |
| 厂商： | ON Semiconductor |
| 文件页数： | 11/15页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR FLYBACK PWM 7-PDIP |
| 产品变化通告： | Product Obsolescence 01/Jul/2009 |
| 标准包装： | 1 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 100kHz |
| 电源电压： | 8.2 V ~ 18 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： | 无 |
| 工作温度： | 0°C ~ 125°C |
| 封装/外壳： | 8-DIP（0.300"，7.62mm），7 引线 |
| 包装： | 剪切带 (CT) |
| 其它名称： | NCP1378PGOSCT |
NCP1378
CTN
NCP1378
1
8
Aux.
1
NCP1378
8
Aux.
ON/OFF
2
3
7
6
2
3
4
7
6
5
4
5
VCCcap
Figure 24. A simple CTN triggers the latchoff as
soon as the temperature exceeds a given setpoint.
Shutting Off the NCP1378
Shutdown can easily be implemented through a simple
NPN bipolar transistor as depicted by Figure 6. When OFF,
Q1 is transparent to the operation. When forward biased,
the transistor pulls the FB pin to ground (Vcesat ≈
200 mV) and permanently disables the IC. A small time
constant on the transistor base will avoid false triggering
(Figure 26).
NCP1378
Figure 25. A simple transistor arrangement allows
to trigger the latchoff by an external signal.
optocoupler LED. As a result, the auxiliary voltage also
decreases because it also operates in Flyback and thus
duplicates the output voltage, providing the leakage
inductance between windings is kept low. To account for
this situation and properly protect the power supply,
NCP1378 hosts a dedicated overload detection circuitry.
Once activated, this circuitry imposes to deliver pulses in
a burst manner with a low Duty Cycle. The system
auto-- recovers when the fault condition disappears.
During the startup phase, the peak current is pushed to
ON/OFF
10 k
3
2
10 nF
Q1
1
1
2
3
4
8
7
6
5
the maximum until the output voltage reaches its target and
the feedback loop takes over. The auxiliary voltage takes
place after a few switching cycles and self-- supplies the IC.
In presence of a short circuit on the output, the auxiliary
voltage will go down until it crosses the undervoltage
lockout level of typically 7.5 V. When this happens,
NCP1378 immediately stops the switching pulses and
unbiases all unnecessary logical blocks. The overall
consumption drops, while keeping the gate grounded, and
Figure 26. A Simple Bipolar Transistor Totally
Disables the IC
Overload Operation
In applications where the output current is purposely not
controlled (e.g. wall adapters delivering raw DC level), it
is interesting to implement a true short-- circuit protection.
A short-- circuit actually forces the output voltage to be at
the V CC slowly falls down. As soon as V CC reaches
typically 5.5 V, the startup source turns-- on again and a new
startup sequence occurs, bringing V CC toward 8.4 V as an
attempt to restart. If the default has gone, then the power
supply normally restarts. If not, a new protective burst is
initiated, shielding the SMPS from any runaway.
Figure 27 portrays the typical operating signals in short
circuit.
a low level, preventing a bias current to circulate in the
http://onsemi.com
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相关代理商/技术参数 |
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| NCP1379 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Quasi-Resonant Current-Mode Controller for High-Power Universal Off-line Supplies |
| NCP1379_11 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Quasi-Resonant Current-Mode Controller for High-Power Universal Off-line Supplies |
| NCP1379DR2G | 功能描述:电流型 PWM 控制器 QUASI-RES CUR MODE CONTRL 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 |
| NCP1380 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Quasi-Resonant Current-Mode Controller for High-Power Universal Off-Line Supplies |
| NCP1380_12 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Quasi-Resonant Current-Mode Controller for High-Power Universal Off-Line Supplies |
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