**Table of Contents** 1. Working Mode Analysis of Flyback Converter 2. Key Waveform Analysis of Flyback Converter 3. RCD Absorption Circuit Design and Switching Device Stress 4. Understanding Noise Circuits and Wiring Layout 5. Practical Project-Based Flyback Power Supply Video Tutorial **Modal Analysis of the Flyback Converter** When the switch is turned on, the primary winding of the transformer is charged, the diode is off, and the load is powered by the output filter capacitor. When the switch is turned off, the diode turns on, allowing the energy stored in the transformer to be transferred to the load side through the diode. The basic input-output relationship of a flyback converter can be expressed as: $$ V_{out} = \frac{N_2}{N_1} \cdot \frac{D}{1-D} \cdot V_{in} $$ where $ D $ is the duty cycle, $ N_1 $ and $ N_2 $ are the number of turns in the primary and secondary windings, respectively. **Ideal Switching Waveforms** The ideal switching waveforms for a flyback converter show clear on and off states of the switch, with smooth transitions between them. **Key Waveform Analysis of Flyback Converter** **MOSFET DS Voltage Waveform in DCM Mode** In Discontinuous Conduction Mode (DCM), the MOSFET's drain-to-source voltage waveform shows a clear drop when the switch turns off, followed by a resonant spike due to parasitic capacitance and inductance. **MOSFET DS Voltage Waveform in CCM Mode** In Continuous Conduction Mode (CCM), the voltage waveform is more stable, but still exhibits some ringing due to the parasitic elements. **Current Spike on the Switch Tube** After the switch turns off, the secondary side of the transformer is clamped by the output voltage $ V_o $. The parasitic capacitor $ C_p $ charges up to $ nV_o $, and during turn-on, it discharges through the primary winding. This creates a resonant circuit between the parasitic inductance and the input voltage, resulting in a current spike. **Design of RCD Passive Absorption Circuit** An RCD snubber circuit is commonly used to dampen the voltage spikes across the MOSFET, improving the reliability and efficiency of the power supply. **Stress Analysis of Switching Devices** - **Main Switch S1 Voltage Stress**: The voltage stress on the main switch depends on the input voltage and the turns ratio of the transformer. - **Rectifier Diode D1 Voltage Stress**: The reverse voltage across the rectifier diode is determined by the output voltage and the transformer's turns ratio. **Flyback Noise Loop and Layout Requirements** Flyback converters are known for generating high-frequency noise due to their switching nature. To minimize this, proper layout techniques such as single-point grounding, reducing loop area, and using high-frequency capacitors are essential. **Common Flyback Topology** Several topologies exist for flyback converters, including the basic single-switch configuration, multi-output designs, and isolated configurations. Each has its own advantages and challenges. **Noise Reduction Techniques** By carefully routing the high-current loops and placing decoupling capacitors close to the switching components, the noise generated by the converter can be significantly reduced. Additionally, minimizing ground impedance through proper PCB layout helps improve overall performance. This detailed analysis provides a comprehensive understanding of flyback converter operation, key waveforms, and practical design considerations for real-world applications.

Plane Diffraction Grating

Planar gratings are mainly used for spectrum analysis and light wavelength measurement. It is an optical device composed of a large number of parallel slits of equal width and equal distance. There are many types of gratings. The commonly used grating is made by engraving a large number of parallel notches on the glass. The nicks are divided into opaque parts, and the smooth part between the two nicks can transmit light. The exquisite grating produced by our company has thousands to tens of thousands of nicks within 1CM width, and the light passes through the grating. The resulting spectrum is the result of single-slit diffraction and multi-slit interference.

Plane Diffraction Grating,Reflective Grating,Light Grating,Optical Grating

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