g******u 发帖数: 3060 | 1 抱歉,原来发在英文论坛上的,就直接转贴了。
I built a power-factor-corrected battery charger using Fairchild's
FAN7529 PFC chip and Onsemi's UC2843 constant frequency PWM chip. Basically
it's a boost converter driven by FAN7529 followed by 2843 chip driven
flyback.
It worked fine on my bench for hours. But the customer made a test on a
very deeply discharged battery set (somehow discharged to 8V for 24V
batteries, near dead ones to me) and they said something was not ideal.
When I re-test the returned unit, | E*****a 发帖数: 757 | 2 你的Ct有没有温度或者电压derating的问题??
换个好的Ct看看?
Basically
up
【在 g******u 的大作中提到】 : 抱歉,原来发在英文论坛上的,就直接转贴了。 : I built a power-factor-corrected battery charger using Fairchild's : FAN7529 PFC chip and Onsemi's UC2843 constant frequency PWM chip. Basically : it's a boost converter driven by FAN7529 followed by 2843 chip driven : flyback. : It worked fine on my bench for hours. But the customer made a test on a : very deeply discharged battery set (somehow discharged to 8V for 24V : batteries, near dead ones to me) and they said something was not ideal. : When I re-test the returned unit,
| j***j 发帖数: 324 | 3 1 , change to a new chip to see if it is because of that.
2, if same performance, check that if not in the deep discharged cases, it
still behave weird...( i guess not)...which means that it is only the
problem when output voltage is low...
3, not sure how you generate the Vcc, if Vcc comes from the output voltage,
that may be the problem of UVLO (not sure). Anyway, you can try to connect
Vcc with a constant external power supply to see if it helps...
if every setup is ok, but problem is still
【在 g******u 的大作中提到】 : 抱歉,原来发在英文论坛上的,就直接转贴了。 : I built a power-factor-corrected battery charger using Fairchild's : FAN7529 PFC chip and Onsemi's UC2843 constant frequency PWM chip. Basically : it's a boost converter driven by FAN7529 followed by 2843 chip driven : flyback. : It worked fine on my bench for hours. But the customer made a test on a : very deeply discharged battery set (somehow discharged to 8V for 24V : batteries, near dead ones to me) and they said something was not ideal. : When I re-test the returned unit,
| g******u 发帖数: 3060 | 4 你是个天才。
确实那个timing电容坏了。现在一切正常。
奇怪的是它的电压和温度rating都挺高的,不至于坏。
也排除了污染的问题。
【在 E*****a 的大作中提到】 : 你的Ct有没有温度或者电压derating的问题?? : 换个好的Ct看看? : : Basically : up
| E*****a 发帖数: 757 | 5 谢谢褒奖。
焊接的时候温度高就可能坏。而且根本看不出来。或者在周围吹过热风
【在 g******u 的大作中提到】 : 你是个天才。 : 确实那个timing电容坏了。现在一切正常。 : 奇怪的是它的电压和温度rating都挺高的,不至于坏。 : 也排除了污染的问题。
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