小弟現(xiàn)在調(diào)個6599的電源

在調(diào)的過程中有個問題很奇怪.想請教下各路高手!

 在PDF資料中的電路里LINE腳是由2個3M+8.2K+24.9K的電阻分壓得到的.

問題是安照官方的資料,算出來8.2K+24.9K的電阻是的電壓.也就是L6563的PFC-ok的引腳上電壓肯定是超過2.5V的.

但是6563的資料里卻說.如果PFC-OK引腳上的電壓超過2.5V .PWM將停止輸出.

原話是:

PFC pre-regulator output voltage monitoring/disable function. This pin senses the output
voltage of the PFC pre-regulator through a resistor divider and is used for protection
purposes. If the voltage at the pin exceeds 2.5V the IC is shut down, its consumption goes
almost to the start-up level and this condition is latched. PWM_LATCH pin is asserted high.
Normal operation can be resumed only by cycling the Vcc. This function is used for
protection in case the feedback loop fails.
If the voltage on this pin is brought below 0.2V the IC is shut down and its consumption is
considerably reduced. To restart the IC the voltage on the pin must go above 0.26V. If these
functions are not needed, tie the pin to a voltage between 0.26 and 2.5 V.

不知道是不是我理解有誤.

我現(xiàn)在做的也確實是只要PFC-OK上的電壓超過了2.5V.IC就停止了.

這個問題很郁悶.

還個請教下主變壓器的Lr值由什么因素決定.調(diào)了很久都沒有調(diào)到理想的結(jié)果.