- 您现在的位置：买卖IC网 > PDF目录1849 > MAX8784ETL+T (Maxim Integrated Products)IC REG STP UP W/AMP 40-TQFN PDF资料下载
参数资料
| 型号： | MAX8784ETL+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 16/24页 |
| 文件大小： | 0K |
| 描述： | IC REG STP UP W/AMP 40-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 应用： | LCD 电视机/监控器 |
| 电源电压： | 4 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 40-WFQFN 裸露焊盘 |
| 供应商设备封装： | 40-TQFN-EP（5x5） |
| 包装： | 带卷 (TR) |
Step-Up Regulator, Internal Charge Pumps, Switch
Control, and Operational Amplifier for TFT LCDs
Negative Charge-Pump Regulator
The negative charge-pump regulator (see Figure 5)
generates the negative supply rail for the TFT LCD gate
driver ICs. The output voltage is set with an external
resistive voltage-divider from its output to REF with the
midpoint connected to FBN. The number of charge-
pump stages and the setting of the feedback divider
determine the output voltage of the negative charge-
pump regulator. The charge-pump controller includes a
high-side p-channel MOSFET (P4) and a low-side
n-channel MOSFET (N4) to control the power transfer
as shown in Figure 7.
The error comparator compares the feedback signal
(FBN) with a 250mV internal reference. If the feedback
signal is above the reference, the charge-pump regula-
tor turns on N4 and turns off P4 when the rising edge of
the oscillator clock arrives, level shifting C (NEG) in par-
allel with the reservoir capacitor C OUT(NEG) . If the volt-
age across C OUT(NEG) minus a diode drop (V NEG -
V DIODE ) is higher than the level-shifted flying capacitor
voltage (-V C(NEG) ), charge flow from C OUT(NEG) to
C (NEG) until the diode D2-B turns off. The falling edge
of the oscillator clock turns off N4 and turns on P4,
The negative charge-pump regulator is enabled when
the step-up regulator reaches regulation. Each time it is
enabled, the negative charge-pump regulator goes
through a soft-start routine by ramping down its internal
reference voltage from 1.25V to 250mV in 128 steps.
The soft-start period is 3ms (typ) and FBN fault detec-
tion is disabled during this period. The soft-start feature
effectively limits the inrush current during startup. The
MAX8784 monitors FBN voltage for undervoltage con-
ditions. If V FBN is continuously above 450mV for
approximately 55ms, the MAX8784 sets a fault latch,
shutting down all outputs except the reference and the
operational amplifiers.
High-Voltage Switch Control
The MAX8784 ’s high-voltage switch control block
(Figure 6) consists of three high-voltage p-channel
MOSFETs: Q1, between POUT and GON, Q2 and Q3
between GON and DRN. Q2 and Q3 are arranged
back-to-back so that GON can be either above or
below DRN. The switch control block is enabled when
V GDEL goes above V REF .
allowing V SUP to charge up flying capacitor C (NEG)
through diode D2-A. If the feedback signal is below the
reference when the rising edge of the oscillator comes,
the regulator ignores this clock edge and keeps P4 on
and N4 off.
GDEL
V CC
Q4
5 μ A
FAUL T
SHDN
SWITCH CONTROL
ERROR
COMPARATOR
SUP
FBN SOFT-START DONE
POUT
0.25V
Q1
V REF
GON
P4
A
OSC
DRVN
C
D2
Q2
N4
B
VGOFF
Q3
100k ?
GND1
C OUT
CTL
DRN
Q5
FBN
Figure 5. Negative Charge-Pump Regulator Block Diagram
REF
Figure 6. High-Voltage Switch Control Block Diagram
16
______________________________________________________________________________________
相关PDF资料 |
PDF描述 |
|---|---|
| MAX8785AETI+T | IC CCFL CTRL 28-TQFN |
| MAX8792ETD+T | IC PWM CTRLR STEP-DWN 14TDFN |
| MAX8794ETB+T | IC DDR LINEAR REG 10-TDFN |
| MAX8795AETJ+C7P | IC TFT-LCD DC/DC CONV 32-TQFN |
| MAX8798ETX+T | IC INTERNAL-SW BOOST REG 36-TQFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8784EVKIT+ | 功能描述:显示开发工具 MAX8784 Eval Kit RoHS:否 制造商:4D Systems 产品:4Display Shields 工具用于评估:?OLED-160-G1, ?OLED-160-G2 接口类型:Serial 工作电源电压:5 V |
| MAX8785AETI+ | 功能描述:显示驱动器和控制器 Full-Bridge CCFL Controller 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 |
| MAX8785AETI+T | 功能描述:显示驱动器和控制器 Full-Bridge CCFL Controller 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 |
| MAX8785AEVKIT# | 功能描述:LED 照明开发工具 MAX8785A Eval Kit RoHS:否 制造商:Fairchild Semiconductor 产品:Evaluation Kits 用于:FL7732 核心: 电源电压:120V 系列: 封装: |
| MAX8785ETI+ | 功能描述:显示驱动器和控制器 Full-Bridge CCFL Controller 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 |
发布紧急采购，3分钟左右您将得到回复。