- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄384654 > MAX1889ETE (MAXIM INTEGRATED PRODUCTS INC) Triple-Output TFT LCD Power Supply with Fault Protection PDF資料下載
參數(shù)資料
| 型號： | MAX1889ETE |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Triple-Output TFT LCD Power Supply with Fault Protection |
| 中文描述： | 2.8 A SWITCHING REGULATOR, 1250 kHz SWITCHING FREQ-MAX, QCC16 |
| 封裝： | 5 X 5 MM, 0.80 MM HEIGHT, ULTRA THIN, QFN-16 |
| 文件頁數(shù)： | 17/32頁 |
| 文件大?。?/td> | 796K |
| 代理商： | MAX1889ETE |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁當(dāng)前第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁
M
Triple-Output TFT LCD Power Supply
with Fault Protection
______________________________________________________________________________________
17
Inductor Selection
The minimum inductance value, peak current rating,
series resistance, and size are factors to consider when
selecting the inductor. These factors influence the con-
verter
’
s efficiency, maximum output load capability,
transient response time, and output voltage ripple. For
most applications, values between 3.3μH and 20μH
work best with the MAX1889
’
s switching frequencies.
The maximum load current, input voltage, output volt-
age, and switching frequency determine the inductor
value. For a given load current, higher inductor value
results in lower peak current and, thus, less output rip-
ple, but degrades the transient response and possibly
increases the size of the inductor. The equations pro-
vided here include a constant defined as LIR, which is
the ratio of the peak-to-peak inductor current ripple to
the average DC inductor current. For a good compro-
mise between the size of the inductor, power loss, and
output voltage ripple, select an LIR of 0.3 to 0.5. The
inductance value is then given by:
where
η
is the efficiency, f
OSC
is the oscillator frequency
(see the
Electrical Characteristics
), and I
MAIN
includes
the primary load current and the input supply currents
for the charge pumps. Considering the typical applica-
tion circuit, the maximum average DC load current
(I
MAIN(MAX)
) is 200mA with a 9V output. Based on the
above equations, and assuming 85% efficiency and a
switching frequency of 1MHz, the inductance value is
9.4μH for an LIR of 0.3. The inductance value is 5.6μH
for an LIR of 0.5. The inductance in the standard appli-
cation circuit is chosen to be 6.8μH.
The inductor
’
s peak current rating should be higher than
the peak inductor current throughout the normal operat-
ing range. The peak inductor current is given by:
Under fault conditions, the inductor current can reach the
internal LX current limit (see the
Electrical Characteristics
).
However, soft saturation inductors and the controller
’
s fast
current-limit circuitry protect the device from failure during
such a fault condition.
The inductor
’
s DC resistance can significantly affect
efficiency due to conduction losses in the inductor.
The power loss due to the inductor
’
s series resistance
(P
LR
) can be approximated by the following equation:
where I
L(AVG)
is the average inductor current and R
L
is
the inductor
’
s series resistance. For best performance,
select inductors with resistance less than the internal
N-channel MOSFET
’
s on-resistance (0.25
typ). To
minimize radiated noise in sensitive applications, use a
shielded inductor.
Output Capacitor
The output capacitor affects the circuit stability and out-
put voltage ripple. A 10μF ceramic capacitor works well
in most applications. Depending on the output capaci-
tor chosen, feedback compensation may be required
or desirable to increase the loop-phase margin or
increase the loop bandwidth for transient response
(see the
Feedback Compensation
section).
The total output voltage ripple has two components: the
capacitive ripple caused by the charging and discharg-
ing of the output capacitance, and the ohm ripple due to
the capacitor
’
s equivalent series resistance (ESR):
where I
PEAK
is the peak inductor current (see the
Inductor
Selection
section). For ceramic capacitors, the output volt-
age ripple is typically dominated by V
RIPPLE(C
). The volt-
age rating and temperature characteristics of the output
capacitor must also be considered.
Step-Up Regulator Compensation
The loop stability of a current-mode step-up regulator
can be analyzed using a small-signal model. In continu-
ous conduction mode (CCM), the loop-gain transfer
function consists of a dominant pole, a high-frequency
pole, a right-half-plane (RHP) zero, and an ESR zero. In
the case of ceramic output capacitors, the ESR zero is at
a very high frequency.
V
V
V
V
I
and
V
I
C
V
V
V
RIPPLE
RIPPLE ESR
≈
)
RIPPLE( )
RIPPLE ESR
PEAK ESR COUT
RIPPLE( )
MAIN
OUT
MAIN
MAIN OSC
IN
=
+
≈
(
)
(
(
),
-
P
I
R
I
V
V
R
LR
LAVG
(
L
MAIN
MAIN
IN
L
=
×
)2
2
I
I
V
V
LIR
2
PEAK
MAIN MAX
MAIN
IN MIN
(
=
+
(
)
)
1
1
η
L
V
V
V
V
I
LIR
IN TYP
(
MAIN
MAIN
IN TYP
(
MAIN MAX OSC
(
=
)
)
)
2
1
-
η
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MAX1889 | Fixed-Point Digital Signal Processor 256-BGA |
| MAX1896 | 1.4MHz SOT23 Current-Mode Step-Up DC-DC Converter |
| MAX1896EUT-T | Fixed-Point Digital Signal Processor 532-FCBGA |
| MAX1898 | Fixed-Point Digital Signal Processor 532-FCBGA |
| MAX1898EUB41 | Linear Charger for Single-Cell Li Battery |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1889ETE+ | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 Quad-Output TFT LCD Power Supply RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| MAX1889ETE+T | 功能描述:LCD 驅(qū)動器 Quad-Output TFT LCD Power Supply RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
| MAX1889ETE-T | 功能描述:LCD 驅(qū)動器 RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
| MAX1889EVKIT | 功能描述:電源管理IC開發(fā)工具 MAX1889 Eval Kit RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
| MAX188ACAP | 功能描述:模數(shù)轉(zhuǎn)換器 - ADC Integrated Circuits (ICs) RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。