Ringing type switching power supply constant current driving circuit

Published:2011/7/15 23:18:00 Author:Christina | Keyword: Ringing type, switching, power supply, constant current, driving circuit | From:SeekIC

In the ringing type switching power supply, the power loss of the driving circuit which supplies the base current to the switching transistor is very large. The voltage UB of the transformer coil NB must ensure the minimum input voltage of the switching transistor to make the fully conduction, and the voltage UB is proportional to the input voltage Vi. When the Vi increases, the driving current Id will increases too, but the base resistance Rb increases the power loss that has the square relationship with the increasing part of Id. When the driving current ID is increasing, the voltage stabilization diode subcircuit current will increase too, and this will cause the oscillation problem, in a certain period of time, the switch works, and in the next period of time, the switch stops working.



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