參數(shù)資料
型號(hào): SP7650
英文描述: Wallmount ULTRX Series Fiberglass Enclosure; NEMA Type:1, 2, 4, 4X, 12, 13; Enclosure Material:Fiberglass; External Height:24.61"; External Width:24.11"; External Depth:12.64"; Enclosure Color:Light Gray
中文描述: 寬輸入電壓范圍第3A,300kHz的降壓穩(wěn)壓器
文件頁數(shù): 6/12頁
文件大?。?/td> 121K
代理商: SP7650
6
Date: 08/24/04
SP7650 Wide Input Voltage Range 3A, 300kHz, Buck Regulator Copyright 2004 Sipex Corporation
THEORY OF OPERATION
zero response is desired, then compensation can
be as simple as an RC to ground. If a more
complex compensation is required, then the
amplifier has enough bandwidth (45
°
at 4 MHz)
and enough gain (60dB) to run Type III compen-
sation schemes with adequate gain and phase
margins at cross over frequencies greater than
50kHz.
The common mode output of the error amplifier
is 0.9V to 2.2V. Therefore, the PWM voltage
ramp has been set between 1.1V and 2.2V to
ensure proper 0% to 100% duty cycle capability.
The voltage loop also includes two other very
important features. One is an asynchronous start
up mode. Basically, the synchronous rectifier
can not turn on unless the high side switch has
attempted to turn on or the SS pin has exceeded
1.7V. This feature prevents the controller from
“dragging down” the output voltage during
startup or in fault modes. The second feature is
a 100% duty cycle timeout that ensures synchro-
nized refreshing of the BST capacitor at very
high duty ratios. In the event that the high side
NFET is on for 20 continuous clock cycles, a
reset is given to the PWM flip flop half way
through the 21st cycle. This forces GL to rise for
the cycle, in turn refreshing the BST capacitor.
The boost capacitor is used to generate a high
voltage drive supply for the high side switch,
which is 5V above V
IN
.
Power MOSFETs
The SP7650 contains a pair of integrated low
resistance N-channel switches designed to drive
up to 3A of output current. Care should be taken
to de-rate the output current based on the ther-
mal conditions in the system such as ambient
temperature, airflow and heat sinking. Maxi-
mum output current could be limited by thermal
limitations of a particular application by taking
advantage of the integrated over temperature
protective scheme employed in the SP7650.
The SP7650 incorporates a built-in over-tem-
perature protection to prevent internal overheat-
ing.
GH
Voltage
GL
Voltage
V(VIN)
0V
-0V
-V(Diode) V
V(VIN)+V(VCC)
BST
Voltage
V(VCC)
TIME
SWN
Voltage
VBST
VSWN
V(VCC)
The SP7650 can be set to different output
voltages. The relationship in the following
formula is based on a voltage divider from the
output to the feedback pin VFB, which is set
to an internal reference voltage of 0.80V.
Standard 1% metal film resistors of surface
mount size 0603 are recommended.
Vout = 0.80V ( R1 / R2 + 1 ) => R2 = R1 / [ (
Vout / 0.80V ) – 1 ]
Where R1 = 68.1K
and for Vout = 0.80V
setting, simply remove R2 from the board.
Furthermore, one could select the value of R1
and R2 combination to meet the exact output
voltage setting by restricting R1 resistance
range such that 50K
< R1 < 100K
for
overall system loop stability.
Setting Output Voltages
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
SP7650_05 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Evaluation Board Manual
SP7650_06 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Wide Input Voltage Range 3A, 300kHz, Buck Regulator
SP7650EB 功能描述:電源管理IC開發(fā)工具 Eval Board for SP7650 Series RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評(píng)估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V
SP7650ER 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述:
SP7650ER/TR 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Wide Input Voltage Range 3A, 300kHz, Buck Regulator