准谐振反激变压器设计

QR Flyback converter design Date : 2006-08-01

By : Martin Hsiao Description Item Unit

Output power Po W22202020 Efficiencyη0.850.850.850.85 Output voltage Vo V20555 Sec. diode forward drop Vf V0.450.450.450.45 Input voltage Vdc V380126400400 Primary turns Np44606060 Secondary Turns No9233 Turn ratio Np:No N 4.8930.0020.0020.00 Reflected voltage NVo V99.98163.50109.00109.00 Primary inductance LpμH5342,0001,0001,000 Resonating cap.Cp pF220700300300 Leakage inductance LleakμH8682020 Switching frequency F kHz147.437.896.796.7 Switching period Tμs 6.7926.4610.3510.35 Effective core corss-section area Ae mm256545454 Max. flux density Bmax mT177.9489.1220.3220.3 Primary peak current Ip A0.8210.7920.7140.714 Primary rms current Iprms A0.1950.3150.1710.171 Current sensing resistor Rs ohm0.6090.6310.7000.700 Current sensing resistor selected Rs-sel ohm0.2000.5000.7000.700

Ip*Rsense V0.1640.3960.5000.500 1.425V : VCO starts, 1.45V : min. freq.Vctrl V 1.336 1.104 1.000 1.000

Output name :Vo-5V???

V-wish V12500 Secondary diode drop Vf V0.450.450.70.7 Secondary turns Ns9200 Secondary turns selected Ns-sel12233 Calculated Vout V-result V12.455 4.75 4.75 PIV of secondary diodes PIV V116.19.224.824.8

Secondary average current Io A 1.30 4.000.000.00 Secondary rms current Isrms Arms 1.8677.6320.0000.000 Secondary rms ripple current Isac-rms Arms 1.3 6.50.00.0 Secondary output power Po-sec W15.62000 Leakage voltage spike Vspike V156.5247.0184.3184.3 NVo+Vdc NVo+Vdc480.0289.5509.0509.0 Peak drain voltage at switch opening Vds peak V636.5536.5693.3693.3 Vds rising slope Vds slope kV/μs 3.7 1.1 2.4 2.4

On duty cycle Don0.1700.4750.1720.172 Reset dytu cycle Doff0.6460.3660.6330.633 (Valley+Rising) duty cycle Dw+Dleak0.1840.1580.1940.194