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參數(shù)資料
| 型號： | SC4808B-1MSTRT |
| 廠商： | Semtech Corporation |
| 英文描述： | High Performance Dual Ended PWM Controller |
| 中文描述： | 高性能雙端PWM控制器 |
| 文件頁數(shù)： | 14/28頁 |
| 文件大小： | 453K |
| 代理商： | SC4808B-1MSTRT |
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14
2006 Semtech Corp.
www.semtech.com
SC4808B-1
POWER MANAGEMENT
Application Information (Cont.)
D<50%
Instability in current mode operation
due to Duty cycle >50%
I
L
: Inductor current
i
L
: Small Inductor current perturbation
I
L
i
L
Note: After afew cycles the perturbation
disappears and stable operation returns.
D=50%
I
L
i
L
i
L
I
L
Note: After afew cycles the perturbation
is still present, although this will cause
jitter, but there is no instability.
D>50%
i
L
Note: After afew cycles the perturbation
becomes larger, and causes instability.
i
L
E
Time
E
Time
E
Time
SLOPE COMPENSATION (Current or Voltage mode of operation)
In applications where a current mode control is used for regulation, the peak inductor current information is used to
produce the average output current. If a small perturbation due to changes in supply voltage or noise pick up is gener-
ated, instability may occur if the duty cycle is >50%.
This phenomenon is graphically shown below. The inductor current and disturbed inductor current are shown for three
different duty cycles conditions.
The top wave form shows the applications where the duty cycle D is less than 50%. As shown, even if an error is
introduced, after only a few cycles the error converges to zero.
The second wave form shows the case where D = 50%. Under this condition, even though the error does not completely
disappear, it stays constant and is not getting larger. This will be seen as jitter at the inductor voltage.
The bottom wave form shows D>50%. As shown, a very small error results in a much larger error only after a few cycles.
This will cause instability in the converter and the average output inductor current. The output load will not be able to be
kept in regulation.
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PDF描述 |
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| SC4808B-2 | High Performance Dual Ended PWM Controller |
| SC4808B-2MSTRT | High Performance Dual Ended PWM Controller |
| SC4808C | High Performance Dual Ended PWM Controller |
| SC4808CMSTRT | High Performance Dual Ended PWM Controller |
| SC4809A | High Performance Current Mode PWM Controller |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SC4808B-2 | 制造商:SEMTECH 制造商全稱:Semtech Corporation 功能描述:High Performance Dual Ended PWM Controller |
| SC4808B-2_09 | 制造商:SEMTECH 制造商全稱:Semtech Corporation 功能描述:High Performance Dual Ended PWM Controller |
| SC4808B-2MSTRT | 制造商:Semtech Corporation 功能描述:Current Mode PWM Controller -0.5V to 18V 250mA 10-Pin MSOP T/R 制造商:Semtech 功能描述:Current Mode PWM Controller -0.5V to 18V 250mA 10-Pin MSOP T/R |
| SC4808BIMS.TR | 制造商:Semtech Corporation 功能描述: |
| SC4808BIMSTR | 制造商:SEMTECH 制造商全稱:Semtech Corporation 功能描述:High Performance Dual Ended PWM Controller |
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