1, UC2843, also known as current driven pulse width modulation chip high-power switching power chip , it is a single-ended output control circuit chip high-power switching power chip , its biggest advantage is that the external components are very few, the wiring is relatively simple, high reliability, Low cost. It can be isolated from the power grid through the high-frequency transformer, and is suitable for the switching power supply below 100W.
2, V. The chip is a medium power pwm controller chip, usually used to make 40-100w switching power supply. thePin 3 of the chip is the starting voltage input terminal, which provides the starting voltage of the switching power supply by connecting the 2MΩ resistor to the positive terminal of the main filter capacitor in series. The 7 pin of the chip is the working voltage input end. After the power supply is started, the auxiliary winding of the transformer can stably provide the working voltage of less than 18V to the chip.
3, there is no certainty. If the cost is limited, it may still be cheaper to use flyback on the premise that the output voltage is not lower than 5V, otherwise, because the output current is large, the forward excitation is better. Half-bridge resonant ics are too expensive.
4, because of the large screen size of the machine, the power consumption of the whole machine exceeds 100W,Therefore, PFC circuit is designed according to national regulations, PFC circuit U7001 chip adopts 8-pin FAN7530, main switching power supply U7002 chip FAN7602, backlight chip U7003 is BD9211F. Sharp 46LX430 power board circuit diagram (see Figure 1) PFC circuit PFC circuit is mainly composed of U7004 (FAN7530), energy storage inductor L700 high-power switch tube Q7005.
5, the ATX power supply adds an auxiliary switching power supply, as shown in the figure.
6, flyback switching power supplyThe output characteristics of the voltage and current are worse than that of the forward switching power supply.
The common high-power switching power supply is the half-bridge double-tap type, with the chip TL494, and the chip that can be interchangeable with TL494 is KA7500 and MB3759. Most of the power supplies of desktop computers are the half-bridge double-clicking type of TL494, and the general high-power iron box power supply is basically the same.
I of IR companyRS2795 (1,2) is an LLC resonant half-bridge converter control integrated circuit, with a maximum operating frequency of 500kHz, minimum minimum and maximum switching frequencies, flexible start frequency and time as well as dead zone time, micro-start and ultra-low static current, with a variety of protection circuits, not needed in LCD and PDP TV, Communication and PC switching power supply as well as home sound system.
Forward excitation, do not consider the limit of 200w flyback, 500w forward excitation limit, as for the use of half bridge or full bridge, depends on the power tube you use, if you use vmos or transistor (bjt)It is necessary to use the full bridge, because there are too few tubes with high current and high voltage, and the igbt is used, and the half bridge can be considered.
A0.8 wire 5, 12v16A0.8 wire 3, 3V0.8 wire 6, 12v2A0.8 wire 1. To do 500W power, the 42 core should be made of good Pc40, H7c4 material, F50Kc, too high 494 is unstable, and it is necessary to do 5w output to drive half bridge or full bridge.
TIUCC12050: This is a high performance, low cost current mode PWM controller for offline and DC-DC converter applications. Its features include adjustable frequency, cycle by cycle current limitation, etc. TI UCC28950: This is a chip for high performance, low standby power offline switching power supply. It integrates a variety of protection functions, such as overvoltage protection, undervoltage protection and so on.
Power management chip model table is as follows: PIC24F32KA301. PIC24F16KA301. PIC24F16KA101. PIC18F14K22. PIC18F14K50. PIC16F1829. PIC16F1509. dsPIC33FJ12MC201. PIC24F08KA101. PIC18F13K22. 1PIC18F13K50. 1PIC16F685. 1PIC16F689. 1PIC16F690.
Generally speaking, the name of the chipset is named after the name of the Northbridge chip, such as the Intel 875P chipset's Northbridge chip is 82875P, and the latest is to support dual-core processorsIC24F08KA101. PIC18F13K22. 1PIC18F13K50. 1PIC16F685. 1PIC16F689. 1PIC16F690.
2, TI UCC12050: This is a high performance, low cost current mode PWM controller for offline and DC-DC converter applications. Its features include adjustable frequency, cycle by cycle current limitation, etc. TI UCC28950: This is a chip for high performance, low standby power offline switching power supply. It integrates a variety of protection functionsCan, such as overvoltage protection, undervoltage protection, etc.
3, TNY278PN: This is a commonly used integrated switching power supply chip, with 8-pin package, can provide stable voltage and current output. LNK364PN: This is another common 8-pin integrated switching power supply chip for low-power applications with overload protection and overtemperature protection.
4, the current commonly used chip: TL49TL59SG3524 is used to drive dual-channel bipolar transistor, SG3525 is a dual-way totem pole output can drive dual-channel MOSFET, dual-way drive can be usedDrive half bridge or full bridge type forward switching power supply, the power is generally from tens of watts to tens of kilowatts. UC384UC384UC3845 is generally used for flyback switching power supplies, the power is generally a few watts to several hundred watts.
5, L780L781L780L7815. L7805: is a commonly used three-end regulator with an output voltage of 5V and an output current of 1A. L7812: Similar to L7805, but with an output voltage of 12V and an output current of 1A. L7808: is A three-terminal 8V regulator with an output current of 0.5A. L7815: is a three-terminal 15V regulator with an output current of 1A.