參數(shù)資料
型號: ISL97522IRZ-TK
廠商: INTERSIL CORP
元件分類: 顯示驅(qū)動器
英文描述: 4-Channel TFT-LCD Supply
中文描述: LIQUID CRYSTAL DISPLAY DRIVER, QCC38
封裝: ROHS COMPLIANT, PLASTIC, MO-220, QFN-38
文件頁數(shù): 12/20頁
文件大小: 418K
代理商: ISL97522IRZ-TK
12
FN7445.0
December 13, 2006
f
S
is the switching frequency; D is the duty cycle.
To overcome the variation in external LX driver R
DS(ON)
, an
input is provided (ILADJ) to accommodate 5 different bands
of R
DS(ON)
by using 5 different selection resistors. Internally,
the ILADJ resistor adjusts two things:
1.the current limit;
2.the current feedback being used.
This keeps the dc-dc loop stable and the current limit the
same over a wide range of external drive FETs.
Alternatively, the current limit can be changed for the same
FET by varying the resistor. This would affect the stability of
the system somewhat (because the current feedback
changes) but be selected appropriately to accommodated
the change. The integrator loop should keep the load
regulation within limits as long as it doesn't run out of
dynamic adjustment range when current feedback gets
larger than intended. This could be determined by
measuring how close to the upper clamp limit the voltage on
the Cint pin voltage gets under maximum load current.
Here are the resistor settings on ILADJ which select the five
R
DS(ON)
ranges:
1/ 0ohms (Cfb factor 1, "Cfb" are the relative current
feedback factors)
2/ 30K (Cfb factor 1/1.8)
3/ 83K (Cfb factor 1/3.3)
4/ 182K (Cfb factor 1/5.7)
5/ >370K (Cfb factor 1/10)
1/ sets maximum internal current feedback and minimum
ILimit, used for low Ron fets.
5/ sets minimum internal current feedback and maximum
ILimit, used for large Ron fets.
The Current limit factors should be the inverse of the Cfb
values.
Input Capacitor
The input capacitor is used to supply the current to the
converter. It is recommended that C
IN
be larger than 10μF.
The reflected ripple voltage will be smaller with larger C
IN
.
The voltage rating of input capacitor should be larger than
maximum input voltage.
Boost Inductor
A 6.8μH inductor is recommended. The inductor must be
able to handle the following average and peak current:
I
D
BOOST MOSFET
Due to the parasitic inductance of the trace, the MOSFET
will experience spikes higher that the output voltage when
the MOSFET turns off. Thus, a MOSFET with enough
voltage margin is needed.
The R
DS(ON)
of the MOSFET is critical for power dissipation
and current limit. A MOSFET with low R
DS(ON)
is desired to
get high efficiency and output current, but very low R
DS(ON)
will reduce the loop stability. A MOSFET with 20m
Ω
to 50m
Ω
R
DS(ON)
is recommended. Some recommended MOSFETs
are shown in Table 2.
Rectifier Diode
A high-speed diode is desired due to the high switching
frequency. Schottky diodes are recommended because of
their fast recovery time and low forward voltage. The rectifier
diode must meet the output current and peak inductor
current requirements.
Output Capacitor
The output capacitor supplies the load directly and reduces
the ripple voltage at the output. Output ripple voltage consists
of two components: the voltage drop due to the inductor ripple
current flowing through the ESR of output capacitor, and the
charging and discharging of the output capacitor.
For low ESR ceramic capacitors, the output ripple is
dominated by the charging and discharging of the output
capacitor. The voltage rating of the output capacitor should
be greater than the maximum output voltage.
D
V
-----------------------
V
O
=
(EQ. 7)
TABLE 2. RECOMMENDED MOSFETs
PART
NUMBER
MANUFACTURER
FEATURE
FDC655AN
Fairchild
Semiconductor
6.3A, 30V, R
DS(ON)
= 23m
Ω
FDS4488
Fairchild
Semiconductor
7.9A, 30V, R
DS(ON)
= 22m
Ω
Si7844DP
Vishay
10A, 30V, R
DS(ON)
= 22m
Ω
20A, 30V, R
DS(ON)
= 30m
Ω
SI6928DQ
Vishay
I
LAVG
-------------
=
(EQ. 8)
I
LPK
I
LAVG
Δ
I
L
2
--------
+
=
(EQ. 9)
V
RIPPLE
I
LPK
ESR
V
-----------------------
V
O
I
OUT
---------------
1
f
S
----
×
×
+
×
=
(EQ. 10)
ISL97522
相關(guān)PDF資料
PDF描述
ISL97632 White LED Driver with Digital Dimming(白色LED驅(qū)動器)
ISL97651 4-Channel Integrated LCD Supply
ISL97651ARTZ-T 4-Channel Integrated LCD Supply
ISL97651ARTZ-TK 4-Channel Integrated LCD Supply
ISL98001CQZ-170 Triple Video Digitizer with Digital PLL
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ISL97536IUZ 功能描述:IC REG BUCK SYNC ADJ 1A 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 類型:降壓(降壓) 輸出類型:兩者兼有 輸出數(shù):1 輸出電壓:5V,1 V ~ 10 V 輸入電壓:3.5 V ~ 28 V PWM 型:電流模式 頻率 - 開關(guān):220kHz ~ 1MHz 電流 - 輸出:600mA 同步整流器:無 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:16-SSOP(0.154",3.90mm 寬) 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:16-QSOP
ISL97536IUZ-T 功能描述:IC REG BUCK SYNC ADJ 1A 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標準包裝:50 系列:- 類型:升壓(升壓) 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:5 V ~ 25 V 輸入電壓:2.3 V ~ 5.5 V PWM 型:電流模式 頻率 - 開關(guān):600kHz,1.2MHz 電流 - 輸出:1A 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-TSSOP,8-MSOP(0.118",3.00mm 寬) 包裝:管件 供應(yīng)商設(shè)備封裝:8-MSOP
ISL97536IUZ-TK 功能描述:IC REG BUCK SYNC ADJ 1A 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標準包裝:50 系列:- 類型:升壓(升壓) 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:5 V ~ 25 V 輸入電壓:2.3 V ~ 5.5 V PWM 型:電流模式 頻率 - 開關(guān):600kHz,1.2MHz 電流 - 輸出:1A 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-TSSOP,8-MSOP(0.118",3.00mm 寬) 包裝:管件 供應(yīng)商設(shè)備封裝:8-MSOP
ISL97631HTZ-T7A 制造商:Intersil Corporation 功能描述:
ISL97631IHTZ 制造商:Intersil 功能描述:6 LEDs Driver with Integrated Schottky Diode with OVP