参数资料
型号: MAX8795A+
厂商: MAXIM INTEGRATED PRODUCTS INC
元件分类: 稳压器
英文描述: 1.6 A SWITCHING REGULATOR, 1400 kHz SWITCHING FREQ-MAX, QCC32
封装: 5 X 5 MM, 0.80 MM HEIGHT, LEAD FREE, MO-220WHHD-2, TQFN-32
文件页数: 5/24页
文件大小: 387K
代理商: MAX8795A+
MAX8795A
TFT-LCD DC-DC Converter with
Operational Amplifiers
_
__
_
1
13
3
Q
R
S
RESET DOMINANT
CURRENT
SENSE
Σ
OSCILLATOR
SLOPE COMP
CLOCK
LX
PGND
FB
COMP
1.233V
1.14V
SOFT-
START
VLIMIT
PWM
COMPARATOR
FAULT
COMPARATOR
ILIM
COMPARATOR
TO FAULT LATCH
ERROR AMP
Figure 3. Step-Up Regulator Functional Diagram
voltage, the controller resets the flip-flop and turns off
the MOSFET. Since the inductor current is continuous,
a transverse potential develops across the inductor that
turns on the diode (D1). The voltage across the induc-
tor then becomes the difference between the output
voltage and the input voltage. This discharge condition
forces the current through the 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.
Gate-On Linear-Regulator Controller, REG P
The gate-on linear-regulator controller (REG P) is an
analog gain block with an open-drain n-channel output.
It drives an external pnp pass transistor with a 6.8k
base-to-emitter resistor (Figure 1). Its guaranteed base-
drive sink current is at least 1mA. The regulator including
Q1 in Figure 1 uses a 0.47F ceramic output capacitor
and is designed to deliver 20mA at 25V. Other output
voltages and currents are possible with the proper pass
transistor and output capacitor. See the
Pass-Transistor
Selection and Stability Requirements sections.
REG P is typically used to provide the TFT-LCD gate
drivers’ gate-on voltage. Use a charge pump with as
many stages as necessary to obtain a voltage exceed-
ing the required gate-on voltage (see the
Selecting the
Number of Charge-Pump Stages section). Note the
voltage rating of DRVP is 36V. If the charge-pump out-
put voltage can exceed 36V, an external cascode npn
transistor should be added as shown in Figure 4.
Alternately, the linear regulator can control an interme-
diate charge-pump stage while regulating the final
charge-pump output (Figure 5).
MAX8795A
DRVP
FBP
VMAIN
FROM CHARGE-PUMP
OUTPUT
npn CASCODE
TRANSISTOR
pnp PASS
TRANSISTOR
VGON
Figure 4. Using Cascoded npn for Charge-Pump Output
Voltages > 36V
MAX8795A
DRVP
FBP
VGON
35V
LX
VMAIN
14V
0.22
F
0.1
F
0.1
F
0.47
F
47pF
150pF
274k
1%
10.2k
1%
6.8k
68pF
Q1
Figure 5. The linear regulator controls the intermediate charge-
pump stage.
相关PDF资料
PDF描述
MAX879CSA IC LOGIC 16213 24-BIT FET BUS-EXCHANGE SWITCH -40+85C TSSOP-56 1500/REEL
MAX9851EVCMODU MAX9851评估板/评估系统
MAX9934FART+T SPECIALTY ANALOG CIRCUIT, PBGA6
MAX9950FCCB SPECIALTY ANALOG CIRCUIT, PQFP64
MAX9966BGCCQ+D Quad, Low-Power, 500Mbps ATE Driver/Comparator
相关代理商/技术参数
参数描述
MAX8795AETJ+ 功能描述:直流/直流开关转换器 TFT-LCD DC/DC Converter RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT
MAX8795AETJ+C7P 功能描述:显示驱动器和控制器 TFT-LCD DC/DC Converter RoHS:否 制造商:Panasonic Electronic Components 工作电源电压:2.7 V to 5.5 V 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:QFN-44 封装:Reel
MAX8795AETJ+T 功能描述:LCD 驱动器 TFT-LCD 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
MAX8795AEVKIT+ 功能描述:电源管理IC开发工具 MAX8795A 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
MAX8795AGCJ/V+ 功能描述:LCD 驱动器 TFT-LCD 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