参数资料
| 型号： | NCP4326DR2 |
| 厂商： | ON Semiconductor |
| 文件页数： | 21/29页 |
| 文件大小： | 0K |
| 描述： | IC SECONDARY CTLR SW PS 16-SOIC |
| 产品变化通告： | Discontinuation 30/Jun/2006 |
| 标准包装： | 2,500 |
| 应用： | 次级控制器，准谐振切换模式电源 |
| 输入电压： | 15V |
| 输出数： | 3 |
| 工作温度： | 0°C ~ 105°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 16-SOIC |
| 包装： | 带卷 (TR) |
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NCP4326
The new patented soft ? start is based on the flux
transformer reconstruction concept with leading edge mode
control during a startup sequence only.
A startup sequence can be arisen with the 3 following
cases:
1. The power supply unit is just plug on the main
supply, in this case there is a general startup.
2. The power supply unit is running but one or the
both outputs are disabled, thus by enabling the
output a new startup happened.
3. The power supply unit is running but the
secondary controller is in standby mode (STBY
pin grounded), when the standby mode is left, a
startup sequence happen if at least one of the
outputs is enable.
The idea of this soft ? start is to reconstruct the flux image
inside the flyback transformer, and to compare this image
with a slow ramp up voltage on enable pin, to generate a
smooth increasing duty cycle in leading edge mode. The
leading edge mode control guarantees that the peak current
ramps up smoothly. Because the secondary duty cycle
finishes at the OFF ? time end and starts just before.
At the end of the off time period and due to the primary
controller running in critical conduction mode; the flux in
the transformer is null, so the peak will start from zero to
reach the nominal value.
Figure 44 illustrates the driver synchronization in
soft ? start sequence.
0
Vsync
ON Tim e
OFF Time
t
Verror
VCt
0 Transfo Flux
EN voltage
0
DRV
0
ID2
0
Figure 44. Startup Sequence Illustrating the Leading Edge Mode Control
t
t
t
t
Due to the internal current source and the external
capacitor connected on enable pin (EN1 and EN2 pin); a
playing with the capacitor value the soft ? start time can be
adjusted to fit the application startup time.
voltage ramp is generated that it fixes the soft ? start time; by
http://onsemi.com
21
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| NCP4326DR2G | 功能描述:初级与次级侧 PWM 控制器 Quasi Resonant Secondary Side 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 |
| NCP4328 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Secondary Side CV/CC Controller |
| NCP4328BSNT1G | 制造商:ON Semiconductor 功能描述:REEL / SECONDARY SIDE CONSTANT V |
| NCP432B | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:Programmable Precision References |
| NCP432BCSNT1G | 制造商:ON Semiconductor 功能描述:PROGRAMMABLE PRECISION RE - Tape and Reel 制造商:ON Semiconductor 功能描述:REEL / PROGRAMMABLE PRECISION RE |
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