参数资料
| 型号： | NCP1397ADR2G |
| 厂商： | ON Semiconductor |
| 文件页数： | 17/27页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR ISO PWM 16-SOIC |
| 标准包装： | 2,500 |
| PWM 型： | 控制器 |
| 输出数： | 1 |
| 频率 - 最大： | 560kHz |
| 占空比： | 52% |
| 电源电压： | 10.3 V ~ 20 V |
| 降压： | 无 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 是 |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 16-SOIC（0.154"，3.90mm 宽）15 引线 |
| 包装： | 带卷 (TR) |
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NCP1397A, NCP1397B
V DD
I charge :
F SW(min) + F SW(max)
S
I dis
Ct
+
+
?
3 V ? 1 V
D
Clk
R
Q
Q
Vref
DT
RDT
Figure 36. Dead ? time Generation
Soft ? Start Sequence
In resonant controllers, a soft ? start is needed to avoid
SS
suddenly applying the full current into the resonating circuit.
Action
With this controller the soft ? start duration is fully adjustable
using eternal components. The purpose of the Soft ? Start pin
is to discharge Soft ? Start capacitor before IC restart and in
case of fault conditions detected by Fault input.
Once the controller starts operation, the Soft ? Start
Target is
capacitor (refer to Figure 37) is fully discharged and thus it
Reached
starts charging from the Rt pin. The charging current
increases operating frequency of the controller above F min .
As the soft ? start capacitor charges, the frequency smoothly
A
B
decreases down to F min . Of course, practically, the feedback
loop is supposed to take over the VCO lead as soon as the
output voltage has reached the target. If not, then the
minimum switching frequency is reached and a fault is
detected on the feedback pin (typically below 300 mV).
Figure 38 depicts a typical LLC startup using NCP1397A/B
controller.
Figure 38. A Typical Startup Sequence on a LLC
Converter Using NCP1397
Please note that the soft ? start capacitor is discharged in the
following conditions:
? A startup sequence
RF(start)
SS
Fmax
Rt
? During auto ? recovery burst mode
? A brown ? out recovery
? A temperature shutdown recovery
CSS
RFmin
RFmax
GND
NCP1397
The skip/disable input undergoes a special treatment.
Since we want to implement skip cycle using this input, we
cannot activate the soft ? start every time the feedback pin
Fstart(adj) ? RFstart/RFmin
Fmin(adj) ? RFmin
Fmax(adj) ? RFmax
Figure 37. Soft ? Start Components Arrangement
stops the operations in low power mode. Therefore, when
the skip/enable pin is released, no soft ? start occurs to offer
the best skip cycle behavior. However, it is very possible to
combine skip cycle and true disable, e.g. via ORing diodes
driving Pin 8. In that case, if a signal maintains the
skip/disable input high long enough to bring the feedback
level down (below 0.3 V) since the output voltage starts to
fall down, then the soft ? start discharge switch is activated.
http://onsemi.com
17
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相关代理商/技术参数 |
参数描述 |
|---|---|
| NCP1397B | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:High Performance Resonant Mode Controller with Integrated High-Voltage Drivers |
| NCP1397BDR2G | 功能描述:电流型 PWM 控制器 NCP1397B 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 |
| NCP1397DR2G | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:High Performance Resonant Mode Controller with Integrated High-Voltage Drivers |
| NCP1398_13 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:High Performance Resonant Mode Controller with Integrated High-Voltage Drivers |
| NCP1398B | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:High Performance Resonant Mode Controller with Integrated High-Voltage Drivers |
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