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參數(shù)資料
| 型號： | CS5174ED8 |
| 廠商： | ON SEMICONDUCTOR |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 1.5 A 280 kHz/560 kHz Boost Regulators |
| 中文描述： | 2.4 A SWITCHING REGULATOR, 620 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | SOIC-8 |
| 文件頁數(shù)： | 12/22頁 |
| 文件大?。?/td> | 184K |
| 代理商： | CS5174ED8 |
CS5171, CS5172, CS5173, CS5174
http://onsemi.com
12
The first zero generated by C1 and R1 is:
1
2 C1R1
The phase lead provided by this zero ensures that the loop
has at least a 45
°
phase margin at the crossover frequency.
Therefore, this zero should be placed close to the pole
generated in the power stage which can be identified at
frequency:
1
2 CORLOAD
where:
C
O
= equivalent output capacitance of the error amplifier
≈
120pF;
R
LOAD
= load resistance.
The high frequency pole, f
P2
, can be placed at the output
filter’s ESR zero or at half the switching frequency. Placing
the pole at this frequency will cut down on switching noise.
The frequency of this pole is determined by the value of C2
and R1:
1
2 C2R1
One simple method to ensure adequate phase margin is to
design the frequency response with a 20 dB per decade
slope, until unitygain crossover. The crossover frequency
should be selected at the midpoint between f
Z1
and f
P2
where
the phase margin is maximized.
fZ1
fP
fP2
Figure 32. Bode Plot of the Compensation Network
Shown in Figure 31
Frequency (LOG)
f
P1
G
D
f
Z1
f
P2
Negative Voltage Feedback
Since the negative error amplifier has finite input
impedance as shown in Figure 33, its induced error has to be
considered. If a voltage divider is used to scale down the
negative output voltage for the NFB pin, the equation for
calculating output voltage is:
2.5 (R1
R2
VOUT
R2)
10 A
R1
+
Figure 33. Negative Error Amplifier and NFB Pin
2 V
200 k
Negative ErrorAmp
R
NFB
R
IN
V
OUT
R1
250 k
R2
It is shown that if R1 is less than 10 k, the deviation from
the design target will be less than 0.1 V. If the tolerances of
the negative voltage reference and NFB pin input current are
considered, the possible offset of the output V
OFFSET
varies
in the range of:
0.0.5 (R1
R2)
R2
(15 A
R1)
VOFFSET
0.0.5 (R1
R2)
R2
(5 A
R1)
V
SW
Voltage Limit
In the boost topology, V
SW
pin maximum voltage is set by
the maximum output voltage plus the output diode forward
voltage. The diode forward voltage is typically 0.5 V for
Schottky diodes and 0.8 V for ultrafast recovery diodes
VSW(MAX)
VOUT(MAX)
VF
where:
V
F
= output diode forward voltage.
In the flyback topology, peak V
SW
voltage is governed by:
VSW(MAX)
VCC(MAX)
(VOUT
VF)
N
where:
N = transformer turns ratio, primary over secondary.
When the power switch turns off, there exists a voltage
spike superimposed on top of the steadystate voltage.
Usually this voltage spike is caused by transformer leakage
inductance charging stray capacitance between the V
SW
and
PGND pins. To prevent the voltage at the V
SW
pin from
exceeding the maximum rating, a transient voltage
suppressor in series with a diode is paralleled with the
primary windings. Another method of clamping switch
voltage is to connect a transient voltage suppressor between
the V
SW
pin and ground.
相關PDF資料 |
PDF描述 |
|---|---|
| CS5174GD8 | 1.5 A 280 kHz/560 kHz Boost Regulators |
| CS5174GDR8 | 1.5 A 280 kHz/560 kHz Boost Regulators |
| CS5172GDR8 | 1.5 A 280 kHz/560 kHz Boost Regulators |
| CS5173GDR8 | 1.5 A 280 kHz/560 kHz Boost Regulators |
| CS5172(中文) | 1.5 A 280 kHz/560 kHz Boost Regulators(1.5 A 280 kHz/560 kHz，升壓調(diào)整器) |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| CS5174ED8G | 功能描述:直流/直流開關調(diào)節(jié)器 1.5A High Efficiency Boost RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| CS5174EDR8 | 功能描述:直流/直流開關調(diào)節(jié)器 1.5A High Efficiency RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| CS5174EDR8G | 功能描述:直流/直流開關調(diào)節(jié)器 1.5A High Efficiency Boost RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| CS5174GD8 | 功能描述:直流/直流開關調(diào)節(jié)器 1.5A High Efficiency RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| CS5174GD8G | 功能描述:直流/直流開關調(diào)節(jié)器 1.5A High Efficiency Boost RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
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