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參數(shù)資料
| 型號： | UC3550L-XX-AF5-R |
| 廠商： | 友順科技股份有限公司 |
| 英文描述： | PWM CONTROLLED，PWM/PFM SWITCHABLE STEP-UP DC-DC CONTROLLER |
| 中文描述： | PWM控制，PWM / PFM切換升壓型DC - DC控制器 |
| 文件頁數(shù)： | 7/10頁 |
| 文件大小： | 203K |
| 代理商： | UC3550L-XX-AF5-R |
UC3550
CMOS
IC
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
QW-R502-082,A
7 of 10
EX T ERNAL COMPONENT S ELECT ION
Inductor Selection
An inductor value of 10uH performs well in most application. The UC3550 series also work with inductors in the
4.7uH to 12uH range. An inductor with higher peak inductor current tends a higher output voltage ripple
output filter capacitor ESR
. The inductor’s DC resistance significantly affects efficiency.
Output Capacitor Selection
The output ripple voltage
I
PEAK
x output filter capacitor ESR
output capacitor Equivalent Series Resistance (ESR). Best performances are obtained with good high frequency
characteristics capacitors and low ESR. The best compromise for the value of the Output Capacitance is 220F
Tantalum Capacitor. The output capacitor as close as possible to the device pins.
Input Capacitor Selection
The Input Capacitor is required to compensate, if present, the series impedance between the Supply Voltage
Source and the Input Voltage of the Application. A value of 10
than 2". In any case we suggest to connect both capacitors, The input capacitor as close as possible to the device
pins.
Diode Selection
The Schottky diode with an high switching speed and a very low Forward Voltage (VF) is needed. Higher VF may
cause lost power as heat in the diode, with a decrease of the Efficiency. Moreover, since the Output Voltage pin is
also used as the device Supply Voltage, the Start-up Voltage (see related plots) is strictly due to the diode Forward
Voltage at the rated Forward Current.
External Component Selection
An enhancement N-channel MOSFET or a bipolar NPN transistor can be used as the external switch transistor.
since enhancement N-channel MOSFET is a voltage driven device, it is a more efficient switch than a BJT transistor.
However, he MOSFET requires a higher voltage to turn on as compared with BJT transistor
For enhancement N-channel MOSFET ( it is especially importance for R
DS
(
ON
),typically<0.1
, threshold voltage,
V
GS
(
TH
) must be<V
OUT
, typically<1.5V.
For bipolar NPN transistor, continuous collector current typically 1A to 4A and V
CE(SAT)
<0.2V. the driving capability
is determined by the DC current gain, H
FE
, of the transistor and the base resistor, Rb. Moreover, a speed-up
capacitor, Cb should be connected in paralled with Rb to reduce switch loss and improve efficiency.
I
PEAK
x
is the product of the peak inductor current and the
F is enough to guarantee stability for distances less
相關(guān)PDF資料 |
PDF描述 |
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| UC3550-XX-AF5-R | PWM CONTROLLED，PWM/PFM SWITCHABLE STEP-UP DC-DC CONTROLLER |
| UC3842AL-D08-T | CURRENT MODE PWM CONTROL CIRCUITS |
| UC3842AL-S08-R | CURRENT MODE PWM CONTROL CIRCUITS |
| UC3842AL-S08-T | CURRENT MODE PWM CONTROL CIRCUITS |
| UC3842A-S08-R | CURRENT MODE PWM CONTROL CIRCUITS |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| UC3550-XX-AF5-R | 制造商:UTC-IC 制造商全稱:UTC-IC 功能描述:PWM CONTROLLED，PWM/PFM SWITCHABLE STEP-UP DC-DC CONTROLLER |
| UC3551 | 制造商:UTC-IC 制造商全稱:UTC-IC 功能描述:ADVANCED PWM STEP-UP DC-DC CONVERTER |
| UC3551G-AG6-R | 制造商:UTC-IC 制造商全稱:UTC-IC 功能描述:ADVANCED PWM STEP-UP DC-DC CONVERTER |
| UC3551L-AG6-R | 制造商:UTC-IC 制造商全稱:UTC-IC 功能描述:ADVANCED PWM STEP-UP DC-DC CONVERTER |
| UC3552 | 制造商:UTC-IC 制造商全稱:UTC-IC 功能描述:PWM DC-DC CONVERTER WITH INTERNAL SWITCH AND SOFT-START |
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