小弟现在调个6599的电源
在调的过程中有个问题很奇怪.想请教下各路高手!
在PDF资料中的电路里LINE脚是由2个3M+8.2K+24.9K的电阻分压得到的.
问题是安照官方的资料,算出来8.2K+24.9K的电阻是的电压.也就是L6563的PFC-ok的引脚上电压肯定是超过2.5V的.
但是6563的资料里却说.如果PFC-OK引脚上的电压超过2.5V .PWM将停止输出.
原话是:
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误.
我现在做的也确实是只要PFC-OK上的电压超过了2.5V.IC就停止了.
这个问题很郁闷.
还个请教下主变压器的Lr值由什么因素决定.调了很久都没有调到理想的结果.
