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參數(shù)資料
| 型號： | NCP1200D60R2G |
| 廠商： | ON SEMICONDUCTOR |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | PWM Current-Mode Controller for Low-Power Universal Off-Line Supplies |
| 中文描述： | 0.25 A SWITCHING CONTROLLER, 70 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | LEAD FREE, SOIC-8 |
| 文件頁數(shù)： | 8/16頁 |
| 文件大?。?/td> | 151K |
| 代理商： | NCP1200D60R2G |
NCP1200
http://onsemi.com
8
3. Permanently force the V
CC
level above V
CCH
with
an auxiliary winding. It will automatically
disconnect the internal startup source and the IC
will be fully selfsupplied from this winding.
Again, the total power drawn from the mains will
significantly decrease. Make sure the auxiliary
voltage never exceeds the 16 V limit.
Skipping Cycle Mode
The NCP1200 automatically skips switching cycles when
the output power demand drops below a given level. This is
accomplished by monitoring the FB pin. In normal
operation, pin 2 imposes a peak current accordingly to the
load value. If the load demand decreases, the internal loop
asks for less peak current. When this setpoint reaches a
determined level, the IC prevents the current from
decreasing further down and starts to blank the output
pulses: the IC enters the socalled skip cycle mode, also
named controlled burst operation. The power transfer now
depends upon the width of the pulse bunches (Figure 18 ).
Suppose we have the following component values:
Lp, primary inductance = 1 mH
F
SW
, switching frequency = 48 kHz
Ip skip = 300 mA (or 350 mV / Rsense)
The theoretical power transfer is therefore:
1
2
If this IC enters skip cycle mode with a bunch length of
10 ms over a recurrent period of 100 ms, then the total power
transfer is: 2.2
.
0.1 = 220 mW.
To better understand how this skip cycle mode takes place,
a look at the operation mode versus the FB level
immediately gives the necessary insight:
Lp
Ip
2
Fsw
2.2 W
1.4 V
4.8 V
3.8 V
FB
Normal Current Mode Operation
Skip Cycle Operation
Ip
min
= 350 mV / R
sense
Figure 17. Feedback Voltage Variations
When FB is above the skip cycle threshold (1.4 V by
default), the peak current cannot exceed 1 V/Rsense. When
the IC enters the skip cycle mode, the peak current cannot go
below Vpin1 / 4 (Figure 19). The user still has the flexibility
to alter this 1.4 V by either shunting pin 1 to ground through
a resistor or raising it through a resistor up to the desired
level.
Figure 18. Output pulses at various power levels
(X = 5 s/div) P1<P2<P3
P1
P2
P3
Figure 19. The skip cycle takes place at low peak
currents which guarantees noise free operation
Max Peak
Current
Skip Cycle
Current Limit
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PDF描述 |
|---|---|
| NCP1200D40R2G | PWM Current-Mode Controller for Low-Power Universal Off-Line Supplies |
| NCP1201D100R2G | PWM Current−Mode Controller for Universal Off−Line Supplies Featuring Low Standby Power with Fault Protection Modes |
| NCP1201P60G | PWM Current−Mode Controller for Universal Off−Line Supplies Featuring Low Standby Power with Fault Protection Modes |
| NCP1201P60 | PWM Current-Mode Controller for Universal Off-Line Supplies Featuring Low Standby Power with Fault Protection Modes |
| NCP1201D100R2 | PWM Current-Mode Controller for Universal Off-Line Supplies Featuring Low Standby Power with Fault Protection Modes |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| NCP1200D60R2G-CUT TAPE | 制造商:ON 功能描述:NCP1200 Series 16 V 70 kHz Surface Mount PWM Current-Mode Controller - SOIC-8 |
| NCP1200P100 | 功能描述:電流型 PWM 控制器 100KHz Current Mode RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| NCP1200P100G | 功能描述:電流型 PWM 控制器 100KHz Current Mode SMPS PWM RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| NCP1200P100G | 制造商:ON Semiconductor 功能描述:Pulse Width Modulation (PWM) Controller |
| NCP1200P100R2G | 制造商:ON Semiconductor 功能描述: |
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