Changhong DVB-2000 digital satellite receiver switching power supply circuit

  
Changhong DVB-2000 digital satellite receiver switching power supply circuit Rainbow DVB -2000 top box digital satellite receiver switching power supply circuit mainly by the p
Changhong DVB-2000 digital satellite receiver switching power supply circuit - schematic

ower input circuit, an oscillation circuit switch, the DC output circuit is constituted, as shown in FIG. (1) power input circuit shown in FIG circuit, 22V AC B after step-down transformer and a bridge rectifier circuit VD502-VD505 rectifier, the fuse F502 and the power switch K is supplied to the switching power supply circuit. External input 12-2V DC power supply is also supplied through F502 and K switching power supply circuit, the input circuit of a whole series diode VD501. Rectifier diode VD501 mainly serves two functions: O diodes with unidirectional conductivity. Abnormal voltage isolation. AC 22V input isolation and external input DC power supply, AC 220V input, external DC input voltage can not afford the role to prevent the two inputs simultaneously. (2) switch oscillation circuit switching oscillation circuit is composed of a switching transistor VD501, oscillation switch integrated circuit Ul and the like of the switching transformer T501.




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