Power Supply Protection Circuit of TL431

Published:2011/7/24 7:11:00 Author:Michel | Keyword: Power Supply, Protection Circuit | From:SeekIC

The a,b,c,d are power supply protection circuits of TL431.The picture (a) is constant current circuit of TL431 and the constant current I。=UREF/R2.Picture (b) is protection circuit of overvoltage and undervoltage and the voltage is equal to (1+R3/R4)UREF+UBE,when it is under voltage,the voltage is equal to (1+R1/R2)UREF when it is overvoltage.In the formula,UBE is the base-emiting voltage of VT1.Picture (c) is the current-limiting circuit and the limitting current I。=UREF/R2.Picture(d) is voltage monitoring circuit and LED displays when the voltage is lower than (1+R3/R4)UREF and higher than (1+R1/R2)UREF.



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