欧美成人免费电影,国产欧美一区二区三区精品酒店,精品国产a毛片,色网在线免费观看

參數資料
型號: FAN5236QSCX
廠商: FAIRCHILD SEMICONDUCTOR CORP
元件分類: 穩壓器
英文描述: Dual Mobile-Friendly DDR / Dual-output PWM Controller
中文描述: DUAL SWITCHING CONTROLLER, 345 kHz SWITCHING FREQ-MAX, PDSO28
封裝: QSOP-28
文件頁數: 13/20頁
文件大小: 199K
代理商: FAN5236QSCX
FAN5236
PRODUCT SPECIFICATION
REV. 1.1.7 4/4/03
13
The lower MOSFET drive is not turned on until the gate-to-
source voltage of the upper MOSFET has decreased to less
than approximately 1 volt. Similarly, the upper MOSFET is
not turned on until the gate-to-source voltage of the lower
MOSFET has decreased to less than approximately 1 volt.
This allows a wide variety of upper and lower MOSFETs to
be used without a concern for simultaneous conduction, or
shoot-through.
There must be a low-resistance, low-inductance path
between the driver pin and the MOSFET gate for the adap-
tive dead-time circuit to work properly. Any delay along that
path will subtract from the delay generated by the adaptive
dead-time circit and shoot-through may occur.
Frequency Loop Compensation
Due to the implemented current mode control, the modulator
has a single pole response with -1 slope at frequency deter-
mined by load
where R
O
is load resistance, C
O
is load capacitance.
For this type of modulator, Type 2 compensation circuit is
usually sufficient. To reduce the number of external compo-
nents and simplify the design task, the PWM controller has
an internally compensated error amplifier. Figure 13 shows a
Type 2 amplifier and its response along with the responses of
a current mode modulator and of the converter. The Type 2
amplifier, in addition to the pole at the origin, has a zero-pole
pair that causes a flat gain region at frequencies between the
zero and the pole.
This region is also associated with phase ‘bump’ or reduced
phase shift. The amount of phase shift reduction depends the
width of the region of flat gain and has a maximum value of
90 degrees. To further simplify the converter compensation,
the modulator gain is kept independent of the input voltage
variation by providing feed-forward of VIN to the oscillator
ramp.
The zero frequency, the amplifier high frequency gain and
the modulator gain are chosen to satisfy most typical appli-
cations. The crossover frequency will appear at the point
where the modulator attenuation equals the amplifier high
frequency gain. The only task that the system designer has to
complete is to specify the output filter capacitors to position
the load main pole somewhere within one decade lower than
the amplifier zero frequency. With this type of compensation
plenty of phase margin is easily achieved due to zero-pole
pair phase ‘boost’.
Figure 13. Compensation
Conditional stability may occur only when the main load
pole is positioned too much to the left side on the frequency
axis due to excessive output filter capacitance. In this case,
the ESR zero placed within the 10kHz...50kHz range gives
some additional phase ‘boost’. Fortunately, there is an oppo-
site trend in mobile applications to keep the output capacitor
as small as possible.
If a larger inductor value or low ESR values are called for by
the application, additional phase margin can be achieved by
putting a zero at the LC crossover frequency. This can be
achieved with a capacitor across across the feedback resistor
(e.g. R5 from Figure 5) as shown below.
Figure 14. Improving Phase Margin
The optimal value of C(Z) is:
Protection
The converter output is monitored and protected against
extreme overload, short circuit, over-voltage and under-
voltage conditions.
A sustained overload on an output sets the PGx pin low and
latches-off the whole chip. Operation can be restored by
cycling the VCC voltage or by toggling the EN pin.
F
PO
2
R
O
C
O
--------1
=
(7)
F
Z
2
R
2
C
1
---------1
6kHz
=
=
(8a)
F
P
2
R
2
C
2
---------1
600kHz
=
=
(8b)
R1
R2
EA Out
C1
C2
REF
V
IN
Convete
0
14
18
modulator
F
P0
F
Z
F
P
error amp
C(OUT)
VOUT
C(Z)
R5
VSEN
L(OUT)
R6
C Z
----L OUT
)
R5
C OUT
)
×
=
(9)
相關PDF資料
PDF描述
FAN5236 Dual Mobile-Friendly DDR / Dual-output PWM Controller
FAN5240 Multi-Phase PWM Controller for AMD Mobile Athlon TM and Duron TM
FAN5240MTC Multi-Phase PWM Controller for AMD Mobile Athlon TM and Duron TM
FAN5240MTCX Multi-Phase PWM Controller for AMD Mobile Athlon TM and Duron TM
FAN5240QSC Multi-Phase PWM Controller for AMD Mobile Athlon TM and Duron TM
相關代理商/技術參數
參數描述
FAN5240 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Multi-Phase PWM Controller for AMD Mobile Athlon TM and Duron TM
FAN5240_06 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Multi-Phase PWM Controller for AMD Mobile Athlon and Duron
FAN5240_ADC3116B WAF 制造商:Fairchild Semiconductor Corporation 功能描述:
FAN5240MTC 功能描述:開關變換器、穩壓器與控制器 DC/DC RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
FAN5240MTC_Q 功能描述:開關變換器、穩壓器與控制器 DC/DC RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
主站蜘蛛池模板: 丹江口市| 英吉沙县| 安仁县| 老河口市| 通渭县| 巴里| 宁津县| 治县。| 东辽县| 城固县| 松阳县| 车险| 汨罗市| 新竹县| 大英县| 瑞丽市| 芦山县| 南昌市| 牟定县| 盘锦市| 驻马店市| 达孜县| 织金县| 周至县| 宁河县| 双辽市| 达拉特旗| 宜丰县| 双牌县| 保康县| 邵武市| 普宁市| 潍坊市| 惠安县| 北川| 蕉岭县| 德惠市| 兴文县| 青州市| 色达县| 枣庄市|