Master the design of single-ended flyback switching power supply step by step

arui1999

Master the design of single-ended flyback switching power supply step by step [Copy link]

 

■Step 1_Determine application requirements
■Step 2_Select feedback circuit and bias voltage VB according to application requirements
■Step 3_Determine the minimum and maximum DC input voltages VMIN and VMAX, and select the capacity of input storage capacitor CIN based on input voltage and PO
■Step 4_Select input rectifier bridge
■Step 5_Determine the output voltage VOR of the transmitter and the clamping voltage VCLO
■Step 6_Set the current waveform parameter KP corresponding to the corresponding working mode and current waveform: when KP≤1, KP=KRP; when KP≥1, KP=KDP
■Step 7_Determine DMAX according to VMIN and VOR
■Step 8_Calculate primary peak current IP, input average current IAVG and primary RMS current IRMS
■Step 9_Select MOS tube chip based on AC input voltage, VO, PO and efficiency
■Step 10_Set the ILIMIT reduction factor KI for reducing the external current limit point
■Step 11_Verify MOS by comparing IP and ILIMIT Correctness of chip selection
■Step 12_Calculate the thermal resistance of the power switch tube and select the heat sink to verify the correctness of the MOS chip selection
■Step 13_Calculate the primary inductance LP
■Step 14_Select the core and the skeleton, and then get the reference values of Ae, le, AL, and BW from the data sheet of the core and the skeleton
■Step 15_Set the number of layers L of the primary winding and the number of turns of the secondary winding (may need to go through an iterative process)
■Step 16_Calculate the number of turns of the secondary winding and the number of turns of the bias winding
■Step 17_Determine the primary winding wire diameter parameters OD, DIA, AWG
■Step 18_Step 23-Check, and. If necessary, it can be iterated by changing L, or or the core/skeleton method until it meets the specified range
■Step 24 – Confirm that BP≤4200 Gauss. If necessary, reduce the current limit reduction factor
■ Step 25 – Calculate the secondary peak current
■ Step 26 – Calculate the secondary RMS current
■ Step 27 – Determine the secondary winding wire diameter parameters ODS, DIAS, AWGS
■ Step 28 – Determine the output capacitor ripple current
■ Step 29 – Determine the maximum peak reverse voltage PIVS, PIVB of the secondary and bias windings
■ Step 30 – Refer to Table 8 to select the clamping Zener diode and blocking diode used in the primary clamp circuit based on VOR and output type
■ Step 31 – Select the output rectifier according to Table 9
■ Step 32 – Select the output capacitor
■ Step 33 – Select the post-filter inductor L and capacitor C
■ Step 34 – Select the bias winding rectifier from Table 10
■ Step 35 – Select the bias winding capacitor
■ Step 36 – Select the control pin capacitor and series resistor
■ Step 37 – Select the appropriate feedback circuit components according to the type of reference feedback circuit shown in Figures 3, 4, 5 and 6
■ Step 38 – Design the loop dynamic compensation

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869755885

Thank you for sharing. The description is very clear and the power supply knowledge is very rich. I learned a lot. Thank you!

lkh747566933

I can only make the most basic transformer and rectifier power supply. I have never made a switching power supply.