•
U( k ) 0.4 0.2 0 0.4 1 0.8 0.6
PEGASUS
0.5
0.6
0.7 k
0.8
0.9
1
When the voltage had decayed to 70.7% of its initial value, half of the available energy has been extracted.
PEGASUS
开关电源中关键元件的设计 Example for fuse Ele-characteristics
PEGASUS
开关电源中关键元件的设计 Example for fuse Safety approvals
PEGASUS
开关电源中关键元件的设计 Example for fuse Safety approvals
Set
(
)
(
)
k = 0.6 V0 = 310Vdc t = 20mS
That
2⋅ P ⋅t C= 2 ⇒ C = 0.65µF / W 2 Vo (1 − k )
Note: The efficiency had been ignore to simplify the calculation.
开关电源中关键元件的设计
PEGASUS
开关电源中关键元件的设计
Designing for the ELE-Capacitor Holdup Time vs. Bus Voltage • Energy U extracted from the bus capacitor is
1 U = C ⋅ (V0 2 − V12 ) 2 Let V1 = k ⋅ V0 1 Then U = C ⋅V0 2 ⋅ (1 − k 2 ) 2
PEGASUS
开关电源中关键元件的设计
王海杰（jack_wang） 世纪电源网版主 中国电源学会高级会员 2009年3月28日
PEGASUS
开关电源中关键元件的设计
开关电源中关键元件的设计
• Input Fuse • MOV • ELE- Capacitors • Power mosFET • Schottky Diode • Photocoupler
PEGASUS
10
20
30 t
40
50
60
开关电源中关键元件的设计
Designing for the ELE-Capacitor Needed capacitance calculation
suppose
PEGASUS
k=
V final V0
1 1 2 2 W = P ⋅ t = C ⋅ Vo − V final = C ⋅ V0 1 − k 2 2 2
PEGASUS
开关电源中关键元件的设计
Designing for the ELE-Capacitor Loss angle tangent (dissipation factor)
PEGASUS
开关电源中关键元件的设计
Designing for the ELE-Capacitor Loss angle tangent (dissipation factor)
PEGASUS
开关电源中关键元件的设计
Designing for the ELE-Capacitor Impedance vs tempreture
PEGASUS
The impedance varies much due to ESR affected by the temperature
开关电源中关键元件的设计
开关电源中关键元件的设计 Introduce to Metal Oxide Varistor
Maximum Surge Current Derating curves
PEGASUS
The maximum current value will sudden derate with repeated pulse
PEGASUS
开关电源中关键元件的设计 Introduce to Metal Oxide Varistor
Power Derating vs Temperature
PEGASUS
Note: Need to care if some MOV show -40 ~ 125DegreeC operating range
开关电源中关键元件的设计
Power mosFET characteristic
The symbol of a power mosFET
PEGASUS
开关电源中关键元件的设计
Power mosFET characteristic
The mosFET switching waveforms
PEGASUS
Designing for the ELE-Capacitor
PEGASUS
Design for the output capacitor Due to the current characteristic of electrical capacitor, the SMPS output capacitor normally will be decide by the ripple current capability and ESR, just calculate the ripple current and select the capacitance should meet most of application, the think need to care is that the thermal and the life of ele-cap.
开关电源中关键元件的设计
Power mosFET characteristic
Vgs vs Id example
PEGASUS
开关电源中关键元件的设计
Power mosFET characteristic
Qg vs Vds example
PEGASUS
开关电源中关键元件的设计
Power mosFET characteristic
PEGASUS
The tangent shows higher values as the measured frequency increases and the measured temperature decreases.
开关电源中关键元件的设计
Designing for the ELE-Capacitor Impedance and ESR vs frequency
Designing for the ELE-Capacitor Leakage current vs tempreture
PEGASUS
The higher temperature and higher voltage will affect the leakage current
开关电源中关键元件的设计
PEGASUS
Note: Should Simply estimated the maximum I2t Value with 20uS for Design Margin.
开关电源中关键元件的设计 Introduce to Metal Oxide Varistor
PEGASUS
Part Number code for Thinking MOV
PEGASUS
Measured at a frequency of 120Hz and applying a maximum AC voltage of 0.5V rms with a DC bias voltage of 1.5 or 2.0V (JIS C 5101)
开关电源中关键元件的设计
Designing for the ELE-Capacitor Typical capacitance behavior vs temperature
PEGASUS
开关电源中关键元件的设计 I2t Example for Bell fuse 5ET Series
PEGASUS
开关电源中关键元件的设计 I2t Example for Bell fuse 5ET Series
PEGASUS
开关电源中关键元件的设计 Surge current Shape for Combine Wave

开关电源中关键元件的设计 Introduce to Metal Oxide Varistor
PEGASUS
Warning: Around 0.1mA peak leakage current with TVR10471 and 264Vac input
开关电源中关键元件的设计
Designing for the ELE-Capacitor Structure of Aluminum ELE-Capacitors
PEGASUS
开关电源中关键元件的设计
Designing for the ELE-Capacitor The Equivalent Circuit
PEGASUS
开关电源中关键元件的设计
Designing for the ELE-Capacitor Typical capacitance behavior vs frequency
开关电源中关键元件的设计 Introduce to Metal Oxide Varistor
Electrical Characteristics of MOV
PEGASUS
开关电源中关键元件的设计 Introduce to Metal Oxide Varistor
Safety Approval of MOV
开关电源中关键元件的设计
• •
• •