Figure 3 is the circuit diagram of the quasi-resonant flyback switching power supply based on TEA1751. The main components are: Main chip TEA175 transformer T field effect tube S resonant capacitor C output rectifier tube D photocoupler IC reference voltage source IC1, among which TEA1751 has internal starting current source, frequency control, output drive, overheat protection, overvoltage protection, overcurrent protection, overload protection and other circuits.
Abstract: Quasi-resonance is a kind of zero-voltage turn-onng>, the maximum output power reaches 24W.
2, dk124 and dk125 common flyback switching power supply chip , but the specifications are a little bit worse.
3, Qualcomm Snapdragon 778G. DK125 and Snapdragon 778G flyback switching power chip The manufacturing process is the same flyback switching power chip , are TSMC six nanometres flyback switching power chip The performance of Snapdragon 778G is better than DK125, and the compatibility is also better, so DK125 can be directly replaced with Qualcomm Snapdragon 778G.
VIPER12A. The DK106 and VIPER12A are both power management chips and have similar functional features. DK106 is a secondary feedback, flyback AC-DC off-line switching power supply control chip. The VIPER12A is an offline switch stableThe voltage regulator, with MOS tube integrated at the input end, uses an internal PWM regulator to achieve high efficiency conversion.
VIPER12A can directly replace DK106, which is a secondary feedback, flyback ACDC off-line switching power supply control chip. The chip adopts highly integrated CMOS circuit design, with output short circuit, secondary open circuit, over temperature, over voltage and other protection functions. The chip has built-in high-voltage power tube and self-powered line, with few peripheral components, simple transformer design (the transformer that isolates the output circuit only needs two windings) and other characteristics.
The chip is specializedThe chip is controlled by a low-power switching power supply. The functions of each pin are as follows: Gnd ground pin. Fb feedback control. Vcc power supply pin. The 678 Collector output pin is connected to the Collector end of the high voltage switch tube in the chip and is connected to the switching transformer.
Control chip DK125 is secondary feedback, flyback AC-DC flyback off-line switching power supply control chip DK106 chip is a special low-power switching power supply control chip, widely used in power adapters, LED power supply, induction cooker, air conditioning, DVD and other small appliancesProduct DK as a brand, is a relatively small luxury brand, DK as a uniform, is also a relatively small uniform hope my answer will be helpful to you.
TI's UC3842~3844 series, PI has several series, TopSwitch, PeakSwitch, LinkSwitch and LinkSwitch fairy also have several series to openOff the power.
has no impact, it is a series of flyback chips high-power chips to do small power is OK, as long as you do not care about the cost, but there is a problem you are necessary to consider because you are doing graduation design, so it is best to recommend that you change back to small power chips to do.
I personally think that the Italian (Fairchild) 1M0265 of this kind is very good, the circuit is simple and reliable, the price is suitable, although there are PI and STR, but the price is too expensive, especially the PI TOP series, simple, too expensive.
VIPER12A. DKThe 106 and VIPER12A are both power management chips and have similar functional features. DK106 is a secondary feedback, flyback AC-DC off-line switching power supply control chip. The VIPER12A is an off-line switching regulator that integrates a MOS tube at the input and uses an internal PWM regulator to achieve high efficiency conversion.
Integrated chip with KA1M0880BTU, less peripheral circuits, 48W without any problem.
Currently commonly used chips: TL49TL59SG3524 and other used to drive dual-channel bipolar transistorsSG3525 is a two-way totem pole output that can drive a two-way MOSFET, and a two-way driver can be used to drive a half-bridge or full-bridge forward switching power supply, with a power generally ranging 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.
I personally think that the 1M0265 of the Yi Fa (Fairchild) is very goodThe circuit is simple and reliable, the price is suitable, although there are PI and STR, but the price is too expensive, especially the PI TOP series, simple, too expensive.
TI's UC3842~3844 series, PI has several series, TopSwitch, PeakSwitch, LinkSwitch and LinkSwitch also have several series of switching power supply.
With single-ended flyback circuit, the most simple and reliable. Generally 2843842 or 2843844 is used for control. You can also just use the TOP tube,TOP224Y is fine.
DC-DC switching power supply is a power supply that uses modern power electronics technology to control the time ratio of switching tube on and off to maintain a stable output voltage. Switching power supply is generally composed of pulse width modulation (PWM) control IC and MOSFET. With the development and innovation of power electronics technology, switching power supply technology is also constantly innovating.
Especially suitable for cost-sensitive flyback switching power supplies. DK 125 is a secondary feedback, flyback AC-DC off-line switching power supply control chip. High chip adoptionIntegrated CMOS circuit design, with output short circuit, secondary open circuit, over temperature, over voltage and other protection functions. The chip has built-in high-voltage power tube and self-power supply line, with few peripheral components, simple transformer design (transformer does not need power supply winding) and other characteristics.
four. A further disadvantage of the forward transformer switching power supply is that when the control switch is off, the back electromotive force voltage generated by the transformer primary coil is higher than the back electromotive force voltage generated by the flyback transformer switching power supply. Because the general forward transformer switching power supply is working, the duty cycle of the control switch is about 0.5, and the flybackThe duty cycle of the power control switch is relatively small. The main thing is it's hard to tune.
1, different flyback switching power chip Flyback switching power supply Flyback switching power supply chip Transformer core has an air gap, push pullStyle no. Of course, you have to use the core with no air gap on the stuff to leave the air gap to do flyback is okay.
2. The typical circuit of push-pull switching power supply is shown in Figure 6. It belongs to a double-ended conversion circuit, and the magnetic core of the high-frequency transformer works on both sides of the hysteresis loop. The circuit uses two switching tubes VT1 and VT2, the two switching tubes are alternately switched on and off under the control of the external excitation square wave signal, and the square wave voltage is obtained in the transformer T secondary group, which is rectified and filtered into the required DC voltage.
3, flyback Flyback switching power supply chip : The circuit topology is simple and the number of components is small, so the cost is low. However, the magnetic core of the circuit converter is unidirectional magnetized, the utilization rate is low, and the peak current of the switching device is very large, and it is widely used in the small power switching power supply of several watts to tens of watts. Because there is no need to output filter inductance, it is easy to achieve multiple output.