為什么用這個IC短路輸入功率高呀,我輸出功率為5W,電感量為2.8MH
是不是我變壓器電感量有問題呀
VIPER22A短路保護
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@jerry-lin
可以搞定的,在供電上下工夫,調(diào)整供電電路參數(shù),可以加大供電電容試試.電容太小就會不保護.
1.Please check the Vdd voltage during short circuit, could it come down to below 8V?
2. the Current limit of this IC is very wide, from 0.56A to 0.84A. This will make design very difficult for wide range input. Normally, will design the transformer to operate with Ip of 0.56A at lowest line input. To cut conner, can assume operation at nominal input voltage and current limit is 0.7A, then design transformer to operate at this condition, then at high input voltage, make sure that the Vdd will fall below 8V durign short circuit.
2. the Current limit of this IC is very wide, from 0.56A to 0.84A. This will make design very difficult for wide range input. Normally, will design the transformer to operate with Ip of 0.56A at lowest line input. To cut conner, can assume operation at nominal input voltage and current limit is 0.7A, then design transformer to operate at this condition, then at high input voltage, make sure that the Vdd will fall below 8V durign short circuit.
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@fqy0931
Vipper22A有短路保護嗎?還請賜教!據(jù)我所知,此IC只有過功率保護,且是通過VCC電壓實現(xiàn),保護模式也是限功率的方式當(dāng)短路輸出后,反饋增益跑出范圍,使得VCC電壓升高到其保護點實現(xiàn)保護,看看資料
1. Peak current limit Idlim, this will switch off the MOsfet when Id+Ifb reach this level, during short circuit, Vfb will be zero, therefore, the maximum current through the transformer winding will be Idlim. You can then estimate the power into the power supply during short circuit, by knowing the Idlim, Lp.
2. OVP protection by Vddovp, the voltage is 42V. During short circuit, the reflected voltage on the Vdd may reduce, depends on different transformer workmanship, the performance will be different. This feature is good for OVP, but for short circuit, if you rely on this feature,the performance may vary during Mass Production.
2. OVP protection by Vddovp, the voltage is 42V. During short circuit, the reflected voltage on the Vdd may reduce, depends on different transformer workmanship, the performance will be different. This feature is good for OVP, but for short circuit, if you rely on this feature,the performance may vary during Mass Production.
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