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參數(shù)資料
| 型號(hào)： | AND8031 |
| 廠商： | ON SEMICONDUCTOR |
| 英文描述： | Isolated Precision Regulation of a Single 1.8 Volt Output from a Universal Line Input |
| 中文描述： | 孤立調(diào)節(jié)精度1.8伏單從通用線路輸入輸出 |
| 文件頁(yè)數(shù)： | 2/12頁(yè) |
| 文件大?。?/td> | 117K |
| 代理商： | AND8031 |
AND8031/D
http://onsemi.com
2
Since the power level is low, an RC EMC filter is utilized.
The RC filter is not as efficient as an LC, but it uses less
board area and will cost less. 1N4005 600 volt fast diodes
provide the full wave rectification of the AC input. The bulk
capacitor is the filter. The selection of the capacitor is
determined from three factors: input voltage, ripple current
and maximum output ripple. The equations for each are as
follows.
Vdc
Vac ·
2
(eq. 1)
Irms
Ipk2·D
3
(eq. 2)
(Discontinuous
mode only)
Cin
k · Pin (AV)
f · (Vripple (p–p))2
(eq. 3)
Pin
Pout
(eq. 4)
Where k is 1 for AC inputs the peak to peak ripple is 6.0
volts and
η
is estimated to be 70% with the low power level
of the board and the RC input filter. Solving for the equations
above and using 50% for the maximum duty cycle, Vdc
maximum is 375 volts, Vdc minimum is 120 volts, Ipeak and
Irms are solved for in the transformer calculations, Pin is 3.2
watts, and Cbulk is 0.9 uF.
(1)
The transformer converts the rectified line voltage to the
output voltage and is controlled by the MC33363B. To
design the transformer, the following data is necessary. Vdc
minimum is 100 volts (allowing for bulk voltage ripple and
power switch voltage drop), the frequency is 100 kHz, the
maximum duty cycle of the power switch and the reset time
for the secondary are both 45% to maintain discontinuous
conduction, and the secondary diode forward voltage drop
is 0.45 volts (estimated).
Psec
(Vout
Vdiode) · Iout
(eq. 5)
Pin
1
2
(Vdc · Ton)2
Lpri · T
(eq. 6)
, or
Lpri
1
2
(Vdc · Ton)2
Pin · T
(eq. 7)
Ipeak
2 · P ·T
L
(eq. 8)
Lpri
Lsec
Np
Ns
2
(eq. 9)
For the primary side of the transformer, Lpri is 3.16 mH,
Ipeak is 142 milliamperes, ton is 4.5 usec and Irms is 55
milliamperes–rms. For the secondary, Psec is 2.25 watts, L
is 2.28 uH, Ipeak is 4.44 amperes and Irms is 1.72
amperes–rms. The turns ratio is 37.2. The auxiliary winding
is set to 12 volts and 10 milliamperes. Using the secondary
turns ratio, the auxiliary turns ratio is calculated as 6.6 in
reference to the primary.
With the peak primary current and the frequency
determined, the components surrounding the MC33363B
can be selected. Referring to Figures 2 and 3, RT will be set
to 30 k Ohms and CT will be set to 390 pF. The Over Voltage
Protection, pin 11, will not be used. Its main function is for
loss of optocoupler protection. Pin 8, the reference voltage,
requires a 1.0 uF ceramic capacitor for stability. The voltage
compensation and voltage feedback, pins 9 and 10, will be
covered in the feedback section of this document. The Vcc
pin requires a 10 uF capacitor for stability.
1.0 M
f
O
7.0
R
T
, TIMING RESISTOR (k
)
500 k
200 k
100 k
50 k
20 k
10 k
10
15
20
30
50
70
R
T
, TIMING RESISTOR (k
)
0.1
0.8
0.6
0.4
0.2
0.15
7.0
10
15
20
30
40
70
50
0.3
1.0
Figure 2. Oscillator Frequency
versus Timing Resistor
Figure 3. Power Switch Peak Drain Current
versus Timing Resistor
Inductor supply voltage and
inductance value are
adjusted so that I
pk
turn–off
is achieved at 5.0 ms.
V
CC
= 20 V
C
T
= 1.0 mF
T
A
= 25
°
C
V
CC
= 20 V
T
A
= 25
°
C
C
T
= 100 pF
C
T
= 200 pF
C
T
= 500 pF
C
T
= 1.0 nF
C
T
= 2.0 nF
C
T
= 5.0 nF
C
T
= 10 nF
I
P
C
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AND8031D | Isolated Precision Regulation of a Single 1.8 Volt Output from a Universal Line Input |
| AND8039 | The One-Transistor Forward Converter |
| AND8044 | Single-Channel 1206A ChipFET TM Power MOSFET Recommended Pad Pattern and Thermal Performance |
| AND8048 | Dual P-Channel 1.8 V (G-S) MOSFET |
| AND8048D | Dual P-Channel 1.8 V (G-S) MOSFET |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AND8031D | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:Isolated Precision Regulation of a Single 1.8 Volt Output from a Universal Line Input |
| AND8039 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:The One-Transistor Forward Converter |
| AND8044 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:Single-Channel 1206A ChipFET TM Power MOSFET Recommended Pad Pattern and Thermal Performance |
| AND8044/D | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:Single-Channel 1206A ChipFET TM Power MOSFET Recommended Pad Pattern and Thermal Performance |
| AND8048 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:Dual P-Channel 1.8 V (G-S) MOSFET |
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