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

MOS power IC full range

KKST patch plug-in active passive crystal oscillator hot sale 24.576000MHZ

FSP241-4F01 is the switching power supply for 37-42 inch LCD TVs in the Yongshenghong FSP series. The output voltage socket pin function table is provided in Table 1. The LCD TV models that use this switching power supply include CHD-TD370F8, CHD-W370F8, CHD-W370F8P, LT37f8N, LT3788, and more.

1. Basic Circuit Structure: This switching power supply primarily consists of an incoming line anti-interference circuit and bridge rectifier filter circuit, PFC (power factor correction) 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 other components.

2. Introduction to Power Interface Output Voltage: The FSP241-4F01 power supply also employs the IR2184S+TDA4863G+200A6 solution, with its front and rear views shown in Figures 1 and 2. The power supply provides four sets of voltages: the inverter power supply is 24V/9A; the audio supply is 12V/4A; the small signal supply is 5V/3A; and the standby power supply is 5VSTB/1A. Its voltage flow block diagram is shown in Figure 3.

3. Analysis of Power Supply Working Principle:

(1) Incoming Line Anti-Interference and Bridge Rectifier Filter Circuit: The AC voltage of 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, as well as inductors FL1-FL3 to filter out high-frequency interference in the AC power supply. Here, the varistor Z1 prevents AC overvoltage, while CY1, CY2, and CY3, CY4 are common-mode capacitors that suppress asymmetric interference, and CX1 is a differential-mode capacitor that suppresses symmetric interference. The AC voltage then enters the bridge rectifier filter circuit composed of BD1 and L1, C2, C3, C4, D1, C1, generating a DC voltage of approximately 300V, which is sent to the standby power circuit. The anti-jamming and bridge rectification filter circuit is shown in Figure 4.

(2) PFC (Power Factor Correction) Circuit: After the bridge rectifier filter circuit, the PFC circuit further improves the efficiency of the power supply by stabilizing the input voltage and reducing harmonic distortion. The PFC circuit typically includes an inductor, a switch, and a controller. These components work together to ensure the input current is proportional to the input voltage, thereby improving the power factor. The PFC circuit ensures efficient energy transfer from the AC source to the DC bus, preparing the power supply for subsequent stages of operation. (3) Main Power Output Circuit: The main power output circuit generates the required voltages for the different components of the LCD TV. It includes a half-bridge inverter that converts the DC bus voltage into an alternating current suitable for driving the backlight inverter and other components. The half-bridge inverter uses two power transistors to alternately connect and disconnect the DC bus voltage across a transformer, producing the desired AC output. The output voltages are carefully regulated to meet the specific requirements of each component in the TV. (4) Synchronous Rectifier Circuit: The synchronous rectifier circuit enhances the efficiency of the power supply by replacing traditional diodes with transistors in the rectification process. This reduces conduction losses and improves overall efficiency. The synchronous rectifier works in conjunction with the main power output circuit to provide stable and reliable DC voltages to the various subsystems within the TV. (5) Standby Power Supply: The standby power supply, or 5VSTB, provides a low-power output that keeps the TV in a ready state when not in use. This circuit is crucial for maintaining essential functions such as remote control reception and quick startup. The standby power supply is typically derived from the main power output circuit and is designed to consume minimal power during standby mode. (6) Overvoltage Protection Circuit: To protect the sensitive electronic components in the TV, the overvoltage protection circuit monitors the input and output voltages. If an overvoltage condition is detected, the circuit quickly shuts down the power supply to prevent damage. This protection mechanism is essential for ensuring the longevity and reliability of the TV's internal components. (7) Open/Standby Control Circuit: The open/standby control circuit manages the transition between the off and on states of the TV. It allows users to turn the TV on and off via the power button or remote control, while also providing the necessary signals to activate or deactivate various subsystems. This circuit ensures smooth transitions and minimizes power surges during startup and shutdown. In summary, the FSP241-4F01 power supply is a highly efficient and reliable solution for powering LCD TVs in the 37-42 inch range. Its advanced design features, including anti-interference circuits, PFC, and overvoltage protection, ensure optimal performance and safety. The power supply supports multiple output voltages tailored to the needs of different components, making it a versatile choice for modern LCD TVs.