Analysis and overhaul Yongshenghong FSP241-4F01 power supply principle (on) - Power Circuit - Circuit Diagram

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FSP241-4F01 is the switching power supply for 37~42 inch LCD TV in Yongshenghong FSP series. The output voltage socket pin function table is shown in Table 1. The LCD TV models using this switching power supply are: CHD-TD370F8, CHD -W370F8, CHD-W370F8P, LT37f8N, LT3788, etc.

1. Circuit basic structure switching power supply mainly consists of incoming line anti-interference circuit and bridge rectifier filter circuit, PFC (power factor compensation) formation and voltage output circuit, current pulse width modulation circuit, half bridge frequency modulation main power output circuit, synchronous rectifier circuit, Grid voltage and PFC voltage detection circuit, 5VSTB standby voltage generation circuit (sub power supply), open/standby control circuit, overvoltage protection circuit and so on.

2. Power interface output voltage introduction
The FS241-4F01 power supply also uses the IR2184S+TDA4863G+200A6 solution, and its front and back objects are shown in Figures 1 and 2. The power supply outputs four sets of voltages: the inverter power supply is 24V/9A; the sound supply is 12V/4A; the small signal supply is 5V/3A; the standby power supply is 5VSTB/1A, and its voltage flow block diagram is shown in FIG.

3. Analysis of working principle of power supply

(1) Incoming line anti-interference and bridge rectifier filter circuit

The AC voltage 220V first passes through the fuse F1 and enters the overvoltage protection and anti-interference system composed of the varistor Z1, capacitors CY1, CY2, CY3, CY4, CX1 and resistors R1, R2 and inductors FL1-FL3 to filter out. High-frequency interference in the AC power supply, in which the varistor Z1 is to prevent AC overvoltage, CY1, CY2 and CY3, CY4 is a common mode capacitor, suppressing asymmetric interference, and CX1 is a differential mode capacitor to suppress symmetrical interference. Then enter the bridge rectifier filter circuit composed of BD1 and L1, C2, C3, C4, D1, C1, generate DC voltage of about 300V, and send it to the standby power circuit. The anti-jamming and bridge rectification filter circuit is shown in Figure 4.