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参数资料
| 型号： | MAX8752ETA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 7/12页 |
| 文件大小： | 0K |
| 描述： | IC DC-DC CONV TFT LCD 8-TDFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 应用： | 转换器，TFT，LCD |
| 输入电压： | 1.8 V ~ 5.5 V |
| 输出数： | 1 |
| 输出电压： | 1.8 V ~ 13 V |
| 工作温度： | 0°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-WDFN 裸露焊盘 |
| 供应商设备封装： | 8-TDFN-EP（3x3） |
| 包装： | 带卷 (TR) |
TFT LCD Step-Up DC-DC Converter
current trip point each time the internal MOSFET turns
on. As the load changes, the error amplifier sources or
CLOCK
LOGIC
LX
sinks current to the COMP output to set the inductor
peak current necessary to service the load. To maintain
AND DRIVER
GND
stability at high duty cycles, a slope-compensation sig-
nal is summed with the current-sense signal.
IN
STARTUP
OSC
CURRENT LIMIT
SOFT-
START
SLOPE COMP
I LIMIT
On the rising edge of the internal clock, the controller
sets a flip-flop, turning on the n-channel MOSFET and
applying the input voltage across the inductor. The cur-
rent through the inductor ramps up linearly, storing
SHDN
OSCILLATOR
PWM
COMPARATOR
∑
CURRENT
SENSE
ERROR AMP
energy in its magnetic field. Once the sum of the cur-
rent-feedback signal and the slope compensation
exceed the COMP voltage, the controller resets the flip-
flop and turns off the MOSFET. Since the inductor cur-
SUP
LDO
LINEAR
REGULATOR
AND
BOOTSTRAP
MAX8752
1.24V
FB
COMP
rent is continuous, a transverse potential develops
across the inductor that turns on the diode (D1). The
voltage across the inductor then becomes the differ-
ence between the output voltage and the input voltage.
This discharge condition forces the current through the
Figure 2. MAX8752 Functional Diagram
Detailed Description
The MAX8752 is a highly efficient, step-up power sup-
ply designed for TFT-LCD panels. The typical circuit
shown in Figure 1 operates from an input voltage as
low as 1.8V, and produces a MAIN output of 10V at
220mA from 2.5V input while supporting discrete
diode-capacitor charge pumps that produce
-9V at 20mA and +28V at 10mA. If the charge-pump
outputs are not required, the diodes and capacitors
associated with them may be eliminated and the main
output increased to 270mA.
The MAX8752 employs a current-mode, fixed-frequen-
cy, pulse-width modulation (PWM) architecture for fast
transient response and low-noise operation. The high
switching frequency (1.2MHz) allows the use of low-
profile inductors and ceramic capacitors to minimize
the thickness of LCD panel designs. The integrated
high-efficiency MOSFET and the IC ’s built-in digital
soft-start function reduce the number of external com-
ponents required. The output voltage can be set from
V IN to 13V with an external resistive voltage-divider.
The MAX8752 regulates the output voltage through a
combination of an error amplifier, two comparators, and
inductor to ramp back down, transferring the energy
stored in the magnetic field to the output capacitor and
the load. The MOSFET remains off for the rest of the
clock cycle.
At light loads, this architecture allows the MAX8752 to
“skip ” cycles to prevent overcharging the output
capacitor voltage.
In this region of operation, the inductor ramps up to a
peak value of approximately 250mA, discharges to the
output, and waits until another pulse is needed.
Output-Current Capability
The output-current capability of the MAX8752 is a func-
tion of current limit, input voltage, operating frequency,
and inductor value. Because of the slope compensa-
tion used to stabilize the feedback loop, the inductor
current limit depends on the duty cycle. The current
limit is determined by the following equation:
I LIM = (1.162 - 0.361 x D) x I LIM_EC
where I LIM _ EC is the current limit specified at 65% duty
cycle (see the Electrical Characteristics ) and D is the
duty cycle.
The output current capability depends on the current-
limit value and is governed by the following equation:
I OUT ( MAX ) = ? I LIM ?
0 . 5 x D V IN ?
several signal generators (Figure 2). The error amplifier
compares the signal at FB to 1.24V and varies the
COMP output. The voltage at COMP determines the
?
?
? x
f OSC x L ?
V IN
V OUT
x η
_______________________________________________________________________________________
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8753ETI | 功能描述:LCD 驱动器 RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
| MAX8753ETI+ | 功能描述:LCD 驱动器 TFT LCD Step-Up DC/DC Converter RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
| MAX8753ETI+T | 功能描述:LCD 驱动器 TFT LCD Step-Up DC/DC Converter RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
| MAX8753ETI-T | 功能描述:LCD 驱动器 RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
| MAX8753EVKIT | 功能描述:电源管理IC开发工具 MAX8753 Eval Kit RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
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