A, input starting circuit zXaservice manual download site
Between 220 v mains via L1001 to L1002 filtering, anti-interference purification circuit, sent to the output after D1001, C1011 rectifier filter + 300 v dc voltage into the transformer T1011 {3} feet, again from {5} feet output to the IC1011 internal field effect tube drain power supply. At the same time, the 300 v voltage after R1021 and C1021 step-down, filtering to IC1011 {5} feet as the initial starting voltage. When voltage instantaneous {5} feet up to 15.6 V, IC1011 internal start-up, switch tube G conduction. Due to the role of the internal oscillator IC1011 {1} feet output 360 vp - p high-frequency pulse voltage, the switch transformer T1011 give vice winding induction voltage output. zXaservice manual download site
 zXaservice manual download site
 zXaservice manual download site
Second, the output voltage regulation circuit zXaservice manual download site
From T1011 {7}, {8} feet induction output pulse voltage after D1021, C1021 rectifier filter for IC1011 {5} feet start working voltage of 16.8 V, the initial startup switch power supply circuit to stop working. From the T1011 {10}, {11} feet output FL +, FL - filament voltage; {12}, {} 14 feet output - 23 v dc voltage for the use of display driver circuit; {13}, {} 14 feet output 12 v dc voltage for the use of drive circuit; {15}, {16} feet 6.1 V dc voltage output, through IC1111 into 3.3 V for audio and video decoding; 6.1 V also by IC1211 into 5 V for digital analog chips; {15}, {} 17 feet output via D1141, C1137, RR1131 rectifier filter after the current limit, after C1131, L1131 network filtering to Q1131 c, from its e + 9 v output voltage; {15}, {} to 18 feet output via D1131, C1131, PR1141, L1141 rectifier filter after the current limit to Q1141 c, from its e - 9 v voltage output. + 9 v working voltage for the use of AC - 3 system. zXaservice manual download site
IC1011 {6} feet is end oscillator pulse width control. C1021 on 17 v rectifier voltage within the R1031, photoelectric coupler Q1031 photosensitive tube to IC1011 {6} feet, when T1011 secondary voltage rise, the light tube resistance decrease of c, e, the voltage will increase {6} feet, control oscillator within IC1011 output pulse width of the duty ratio decreases, and switch tube G output frequency is decreased, the primary and secondary voltage drop, make T1011 so that the output voltage stability. Conversely, when T1011 secondary voltage drop, voltage lower {6} feet, switch tube G frequency increases, make T1011 winding voltage rise and keep the T1011 on voltage stability. Diagram of Q1101, Q1102 differential amplifier circuit, temperature compensation voltage stabilizing role, mainly to reduce the zero drift and its principle is when the output voltage of 6.1 V, after falling Q1101 base potential decline, Q1101 collector current decreases, and reduce the current through the photoelectric coupler in optical diode, the photosensitive resistance increase tube c, e, the IC1011 {6} feet voltage drop, switch tube G frequency increases, T1011 primary voltage rise, overcome the temperature drift caused by the voltage loss; And vice versa, therefore power source with high stability.

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