- 您现在的位置：买卖IC网 > PDF目录16583 > MAX749CSA (Maxim Integrated Products)IC LCD BIAS SUPPLY DGT ADJ 8SOIC PDF资料下载
参数资料
| 型号： | MAX749CSA |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 5/12页 |
| 文件大小： | 0K |
| 描述： | IC LCD BIAS SUPPLY DGT ADJ 8SOIC |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 100 |
| 应用： | LCD 显示器 |
| 电流 - 电源： | 60µA |
| 电源电压： | 2 V ~ 6 V |
| 工作温度： | 0°C ~ 70°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 8-SOIC |
| 包装： | 管件 |
Digitally Adjustable LCD Bias Supply
+2V TO +6V
INPUT
0.1 μ F
22 μ F
6.2V
V+
POWER-ON
RESET
RESET
6-BIT
COUNTER
6-BIT
CURRENT-OUTPUT
DAC
6.66 μ A TO 20 μ A
R SENSE
CTRL
REF
ADJ
LOGIC
INCREMENT
CS
ON/OFF
SWITCH-
MODE
POWER
SUPPLY
DHI
DLOW
Q1
ZTX750
D1
BIAS
MAX749
GND
FB
R BASE
470 ?
R FB
C COMP
L1
47 μ H
1N5819
V OUT
(NEGATIVE)
22 μ F
30V
Figure 1. Block Diagram, Showing External Circuitry Using a PNP Transistor
_______________Detailed Description
The MAX749 is a negative-output inverting power con-
troller that can drive an external PNP transistor or P-
channel MOSFET. An external resistor and an internal
DAC control the output voltage (Figure 1).
The MAX749 is designed to operate from 2V to 6V inputs,
ideal for operation from low-voltage batteries. In systems
with higher-voltage batteries, such as notebook comput-
ers, the MAX749 may also be operated from the regulat-
ed +5V supply. A high-efficiency +5V regulator, such as
the MAX782, is an ideal source for the MAX749. In this
example, the MAX749 efficiency (80%) is compounded
with the MAX782 efficiency (95%): 80% x 95% = 76%,
which is still high.
Operating Principle
The MAX749 and the external components shown in the
Typical Operating Circuit form a flyback converter.
When the external transistor is on, current flows through
the current-sense resistor, the transistor, and the coil.
Energy is stored in the core of the coil during this phase,
and the diode does not conduct. When the transistor
turns off, current flows from the output through the diode
and the coil, driving the output negative. Feedback con-
trol adjusts the external transistor’s timing to provide a
regulated negative output voltage.
The MAX749’s unique control scheme combines the
ultra-low supply current of pulse-skipping, pulse-fre-
quency modulation (PFM) converters with the high full-
load efficiency characteristic of pulse-width modulation
(PWM) converters. This control scheme allows the
device to achieve high efficiency over a wide range of
loads. The current-sense function and high operating
frequency allow the use of tiny external components.
Switching control is accomplished through the combi-
nation of a current limit in the switch plus on- and off-
time limits (Figure 2).
Once turned on, the transistor stays on until either:
- the maximum on-time one-shot turns it off
(8μs later), or
- the switch current reaches its limit (as determined
by the current-sense resistor and the current
comparator).
_______________________________________________________________________________________
5
相关PDF资料 |
PDF描述 |
|---|---|
| M3AAK-1406J | IDC CABLE - MSC14K/MC14G/MSC14K |
| VE-J1W-EZ-S | CONVERTER MINIMOD DC/DC 5.5V 25W |
| ECM18DSEN-S13 | CONN EDGECARD 36POS .156 EXTEND |
| ECM18DSEH-S13 | CONN EDGECARD 36POS .156 EXTEND |
| A8MMS-3418G | ADM34S/AE34G/ADM34S |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX749CSA+ | 功能描述:其他电源管理 Digitally Adjustable LCD Bias Supply RoHS:否 制造商:Texas Instruments 输出电压范围: 输出电流:4 mA 输入电压范围:3 V to 3.6 V 输入电流: 功率耗散: 工作温度范围:- 40 C to + 110 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-48 封装:Reel |
| MAX749CSA+T | 功能描述:显示驱动器和控制器 Digitally Adjustable LCD Bias Supply 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 |
| MAX749CSA-T | 功能描述:显示驱动器和控制器 Digitally Adjustable LCD Bias Supply 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 |
| MAX749EPA | 功能描述:显示驱动器和控制器 Digitally Adjustable LCD Bias Supply 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 |
| MAX749EPA+ | 功能描述:其他电源管理 Digitally Adjustable LCD Bias Supply RoHS:否 制造商:Texas Instruments 输出电压范围: 输出电流:4 mA 输入电压范围:3 V to 3.6 V 输入电流: 功率耗散: 工作温度范围:- 40 C to + 110 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-48 封装:Reel |
发布紧急采购，3分钟左右您将得到回复。