NCP1605DR2G【PDF 24/32 页】IC PFC CONTROLLER CCM/DCM 16SOIC

收藏本站

您好，
买卖IC网欢迎您。
请登录
免费注册

买卖IC网

Sheet目录45

20页 21页 22页 23页 [24页]25页 26页 27页 28页

NCP1605, NCP1605A, NCP1605B

http://onsemi.com

And pfcOK/REF5V is high when the PFC output

voltage is properly and safely regulated. pfcOK/REF5V

should be used to allow operation of the downstream

converter.

Standby Management

The NCP1605 automatically skips switching cycles when

the power demand drops below a given level. This is

accomplished by monitoring the Pin 1 voltage that must

receive a voltage below 300 mV in light load conditions.

Practically, a portion of the feedback signal of the

downstream converter (or some other signal able to indicate

that the power demand is low) should be applied to Pin 1.

Figure 63. Signal for Standby Detection

Rectified

AC line

NCP1605

PFC stage

Feedback of the

downstream converter

Standby Input

Voltage

SMPS

controller

downstream converter

8 9

In normal operation, the circuit controls the continuous

absorption of the line current necessary for matching the load

power demand. When the voltage applied to Pin 1 goes below

300 mV:

" The output pulses are blanked and Pin 3

CONTROL

) is grounded.

" The output of the PFC stage being not fed any more, it

drops. When the output voltage goes below 95.5% of

the regulation level, the circuit resumes operation until

FLAG1 becomes low (what means that the output

voltage has exceeded the regulation level).

" At that moment, if V

Pin1

is still below 300 mV, a new

skipping phase starts.

In other words, instead of continuously providing the

output with a small amount of power, the circuit operates

from time to time at a higher power level. As an example

and to make it simple, instead of continuously supplying

1% of P

MAX

, the circuit can provide the load with 10% of

MAX

for 10% of the time. The IC enters the socalled skip

cycle mode, also named controlled burst operation. This

burst operation is much more efficient compared to a

continuous power flow as it drastically reduces the number

of pulsations and therefore the switching losses associated

to them.

发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

*型号	*数量	厂商	批号	封装

添加更多采购

采购需求

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

我的联系方式