Output sampling winding isolated switching power supply

Published:2011/11/22 0:07:00 Author:May | Keyword: Switching power supply, output sampling, winding isolated | From:SeekIC

The diagram shows the output sampling winding isolated switching power supply . In diagram, T is high frequency transformer; N2 is self-oscillation positive feedback winding; N3 is the error amplifier , and VTSis thewinding to provide sampling signal; N4, N5are DC output windings. DC output and the power gridare isolated from each other, because N3, N4, N5 are isolated from each other. The power supply has two sets output of 6.3V and 100V DC. 35V voltage is used in error amplifier. When output voltage is increasing, the sampling resistor’s voltage UD is increasing, error amplifier VT3’s collector current is increasing. Positive partial voltage offered to variable resistance tube VT2 by voltage drop of resistor R8 generated by the current is increasing, so that the collector current of VT2 is increasing. The voltage dropping Ucd2 is reduced to be equivalent to the shunt resistor between base of switching tube VT1 and ground.



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