- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄383143 > ISL6235 (Intersil Corporation) Octal D-Type Transparent Latches With 3-State Outputs 20-SOIC -40 to 85 PDF資料下載
參數(shù)資料
| 型號(hào)： | ISL6235 |
| 廠商： | Intersil Corporation |
| 英文描述： | Octal D-Type Transparent Latches With 3-State Outputs 20-SOIC -40 to 85 |
| 中文描述： | 只有先進(jìn)的三重的PWM模式和雙線性電源控制器，用于便攜式應(yīng)用 |
| 文件頁(yè)數(shù)： | 11/14頁(yè) |
| 文件大?。?/td> | 441K |
| 代理商： | ISL6235 |
第1頁(yè)第2頁(yè)第3頁(yè)第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)第10頁(yè)當(dāng)前第11頁(yè)第12頁(yè)第13頁(yè)第14頁(yè)
11
Use a mix of input bypass capacitors to control the voltage
ripple across the MOSFETs. Use ceramic capacitors for the
high frequency decoupling and bulk capacitors to supply the
RMS current. Small ceramic capacitors can be placed very
close to the upper MOSFET to suppress the voltage induced
in the parasitic circuit impedances.
For board designs that allow through-hole components, the
Sanyo OS-CON
TM
series offer low ESR and good
temperature performance.
For surface mount designs, solid tantalum capacitors can be
used, but caution must be exercised with regard to the
capacitor surge current rating. These capacitors must be
capable of handling the surge-current at power-up. The TPS
series available from AVX is surge current tested.
+12V Boost Converter Inductor Selection
The inductor value is chosen to provide the required output
power to the load.
where, V
inmin
is the minimum input voltage, 4.9V; D
max
=
1/3, the maximum duty cycle; R
o
is the minimum load
resistance; V
o
is the nominal output voltage and F is the
switching frequency, 100kHz.
Or, for L in uH, the maximum output current is nominally:
+12V Boost Converter Output Capacitor Selection
The total capacitance on the 12V output should be chosen
appropriately, so that the output voltage will be higher than
the undervoltage limit (9V) when the 5V Main soft-start time
has elapsed. This will avoid triggering of the 12V
undervoltage protection.
The maximum value of the boost capacitor, Comax that will
charge to 9V in the soft start time, T
SS
, is shown below,
where L is the value of the boost inductor.
The output capacitor ESR and the boost inductor ripple
current determines the output voltage ripple. The ripple
voltage is given by:
and the maximum ripple current,
I
L,
is given by:
where L is the boost inductor calculated above, 5V is the
boost input voltage and 3.3
μ
is the maximum on time for the
boost MOSFET.
MOSFET Considerations
The logic level MOSFETs are chosen for optimum efficiency
given the potentially wide input voltage range and output
power requirements. Two N-channel MOSFETs are used in
each of the synchronous-rectified buck converters for the
PWM1 and PWM2 outputs. These MOSFETs should be
selected based upon r
DS(ON)
, gate supply requirements,
and thermal management considerations.
The power dissipation includes two loss components;
conduction loss and switching loss. These losses are
distributed between the upper and lower MOSFETs
according to duty cycle (see the following equations). The
conduction losses are the main component of power
dissipation for the lower MOSFETs. Only the upper
MOSFET has significant switching losses, since the lower
device turns on and off into near zero voltage.
The equations assume linear voltage-current transitions and
do not model power loss due to the reverse-recovery of the
lower MOSFET’s body diode. The gate-charge losses are
dissipated by the ISL6235 and do not heat the MOSFETs.
However, a large gate-charge increases the switching time,
t
SW
which increases the upper MOSFET switching losses.
Ensure that both MOSFETs are within their maximum
junction temperature at high ambient temperature by
calculating the temperature rise according to package
thermal-resistance specifications.
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
I
3.3V AND 5V LOAD CURRENT
INPUT CAPACITANCE RMS CURRENT AT VIN = 10.8V
0
1
2
3
4
5
3.3V
OUT-OF-PHASE
5V
IN-PHASE
FIGURE 4.
INPUT RMS CURRENT VS LOAD
Lmax
2
----------------------------------------------------------------
2
Vo
2
2
×
F
×
=
(EQ. 9)
Imax
----------------
=
(EQ. 10)
Comax
---------
0.115
μ
F
×
=
(EQ. 11)
V
RIPPLE
IL
ESR
×
=
(EQ. 12)
IL
-------
3.3
×
μ
=
(EQ. 13)
P
UPPER
I
------------------------------------------------------------
2
r
IN
×
V
×
I
----------------------------------------------------
V
×
t
×
F
S
×
+
=
P
LOWER
I
--------------------------------------------------------------------------------
2
r
IN
×
V
V
–
(
)
×
=
(EQ. 14)
ISL6235
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ISL6235CA | Octal D-Type Transparent Latches With 3-State Outputs 20-SOIC -40 to 85 |
| ISL6244CR | Octal D-Type Transparent Latches With 3-State Outputs 20-SOIC -40 to 85 |
| ISL6244HR-T | Test Probe; Range:-32deg to 500degF RoHS Compliant: NA |
| ISL6244HRZ | Multi-Phase PWM Controller |
| ISL6244HRZ-T | Multi-Phase PWM Controller |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ISL6235CA | 制造商:Rochester Electronics LLC 功能描述:SYSTEM ELECTRONICS REGULATOR FOR LCD-PC - Bulk |
| ISL6235CA-T | 制造商:Rochester Electronics LLC 功能描述:- Tape and Reel |
| ISL6236 | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:High-Efficiency, Quad-Output, Main Power Supply Controllers for Notebook Computers |
| ISL6236A | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:High-Efficiency, Quad-Output, Main Power Supply Controllers for Notebook Computers |
| ISL6236AIRZ | 功能描述:IC MAIN PWR CTRLR QUAD 32-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標(biāo)準(zhǔn)包裝:43 系列:- 應(yīng)用:控制器，Intel VR11 輸入電壓:5 V ~ 12 V 輸出數(shù):1 輸出電壓:0.5 V ~ 1.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:48-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:48-QFN（7x7） 包裝:管件 |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。