请教各位DX．单端反激开关变压器参数搞不懂啊(芯片是L6561)!

1. Design Specifications:
- Mains voltage range: VACmin = 88 Vac, VACmax = 264 Vac
- Minimum mains frequency: fL = 50 Hz
- DC Output Voltage: Vout = 15 V
- Maximum output current: Iout = 2A
- Maximum 2fL output ripple: DVo = 1V peak-to-peak
2. Pre-design Choices:
- Minimum switching frequency: fswmin = 25 kHz
- Reflected voltage: VR = 100V ??此反射电压怎么来的啊
- Leakage inductance overvoltage: DV =70V
- Expected efficiency: h = 85%
3. Preliminary Calculations:
AN1059 APPLICATION NOTE
- Maximum Input Peak Voltage: VPKmin = VACmin × Ö``2 = 264 × Ö``2 = 373V
- Maximum Output Power: Pout = Vout × Iout = 15 × 2 = 30W
- Maximum Input Power: Pin =
Pout
h
× 100 =
30
85
× 100 = 35.3W
- Peak-to-reflected Voltage Ratio: Kv =
VPKmin
VR
=
120
100
= 1.2
- Characteristic functions value: F1(1.2)=0.343; F2(1.2)=0.254; F3(1.2)=0.209; F5(1.2)=0.108???
这里的F1 F2 F3 F5又是从那里换算来的哪!
4. Operating Conditions:
- Peak Primary Current: IPKp =
2 × Pin
VPKmin × F2(Kv)
=
2 × 35.3
120 × 0.254
= 2.32A
- RMS Primary Current: IRMSp = IPKp × Ö``F2`(`Kv)
3
= 2.32 × Ö``0.`2`54
3
= 0.675A
- Peak Secondary current: IPKs =
2 × Iout
Kv × F2(Kv)
=
2 × 2
1.2 × 0.254
= 13.1A
- RMS Secondary Current: IRMSs = IPKs × Ö``Kv` × ```
F3(Kv)
3
= 13.1 × Ö``1.`2 `× ```
0.209
3
= 3.79A
5. Transformer:
- Primary inductance: Lp =
VPKmin
(1 + Kv) × fswmin × IPKp
=
120
(1 + 1.2) × 25 × 103 × 2.32
= 940mH
- Primary-to-secondary turns ratio: n =
VR
(Vout + Vf)
=
100
15 + 0.6
= 6.41

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再附完整官方提供l6561单端反激的应用资料1152664920.rar