Over voltage, over current protection circuit

Published:2011/8/26 3:32:00 Author:Jessie | Keyword: over voltage, over current, protection | From:SeekIC

During normal working, Tr1 and Tr2 are both disconnected, 555 resets, the discharge transistor in 555 is connected, it drains current from the base of Tr3, so that Tr3 is saturated, power 5 to 12V is directly sent to lord load. When load current exceeds prescribed value, Rsc's pressure drop increases, Tr1 is connected, 555 istriggered, internal discharge transistor stop, then Tr1 disconnected too, isolate the source and load, then 555 is monostable, reach single firm time, as long as the load flow phenomena is not ruled out, 555 will trigge again, Tr3 will still isolate load.



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