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1. Select the primary induced voltage VOR
This value is set by you and determines the duty cycle of the power supply. When the switch is open, the primary side is equivalent to the inductor. When a voltage is applied across the inductor, the current value does not change suddenly but rises linearly. When the switch turns off, the primary inductor discharges and the inductor current drops again.
2. Determine the parameters of the primary current waveform
The edge current waveform has three parameters: average current, root mean square current and peak current. Because the output power divided by the efficiency is the input power, and then the input power divided by the input voltage is the input current, which is the average current. Therefore, corresponding to the same power, that is, when the input current is the same, its effective value is related to these parameters. Appropriate adjustment of parameters can minimize the effective value, minimize heat generation and optimize the design.
3. Selection of transformer core
This is based on experience. If you can't choose one, you can estimate one and do the math. If it doesn't work, you can replace it with a large or small size. However, there are formulas or area diagrams on how to select cores based on power. You may wish to refer to them. Many usually come from experience.
4. Determine the parameters of the feedback winding
The feedback voltage is the flyback voltage, which is taken from the output stage, and the feedback voltage is stable. The supply voltage at the top is 5.7-9V. After 7 turns, the voltage is about 6V, which is normal. Remember that the feedback voltage is flyback and its turns ratio must correspond to the amplitude edge. As for the wire, since the current flowing through it is very small, wires that bypass the primary side can be used without strict requirements.
This value is set by you and determines the duty cycle of the power supply. When the switch is open, the primary side is equivalent to the inductor. When a voltage is applied across the inductor, the current value does not change suddenly but rises linearly. When the switch turns off, the primary inductor discharges and the inductor current drops again.
2. Determine the parameters of the primary current waveform
The edge current waveform has three parameters: average current, root mean square current and peak current. Because the output power divided by the efficiency is the input power, and then the input power divided by the input voltage is the input current, which is the average current. Therefore, corresponding to the same power, that is, when the input current is the same, its effective value is related to these parameters. Appropriate adjustment of parameters can minimize the effective value, minimize heat generation and optimize the design.
3. Selection of transformer core
This is based on experience. If you can't choose one, you can estimate one and do the math. If it doesn't work, you can replace it with a large or small size. However, there are formulas or area diagrams on how to select cores based on power. You may wish to refer to them. Many usually come from experience.
4. Determine the parameters of the feedback winding
The feedback voltage is the flyback voltage, which is taken from the output stage, and the feedback voltage is stable. The supply voltage at the top is 5.7-9V. After 7 turns, the voltage is about 6V, which is normal. Remember that the feedback voltage is flyback and its turns ratio must correspond to the amplitude edge. As for the wire, since the current flowing through it is very small, wires that bypass the primary side can be used without strict requirements.
