- 您现在的位置：买卖IC网 > PDF目录383332 > MAX1706 (Maxim Integrated Products, Inc.) 1- to 3-Cell, High-Current, Low-Noise, Step-Up DC-DC Converters with Linear Regulator PDF资料下载
参数资料
| 型号： | MAX1706 |
| 厂商： | Maxim Integrated Products, Inc. |
| 元件分类： | DC/DC变换器 |
| 英文描述： | 1- to 3-Cell, High-Current, Low-Noise, Step-Up DC-DC Converters with Linear Regulator |
| 中文描述： | 1至3节电池、大电流、低噪声、升压型DC-DC转换器，带有线性稳压器 |
| 文件页数： | 12/20页 |
| 文件大小： | 215K |
| 代理商： | MAX1706 |
M
1- to 3-Cell, High-Current, Low-Noise,
Step-Up DC-DC Converters with Linear Regulator
12
______________________________________________________________________________________
current limit for the MAX1705, and 950mA (max) for the
MAX1706. During PWM operation, the circuit operates
with a continuous inductor current.
Synchronized PWM Operation
The MAX1705/MAX1706 can also be synchronized to a
200kHz to 400kHz frequency by applying an external
clock to CLK/SEL. This allows the user to set the har-
monics, to avoid IF bands in wireless applications. The
synchronous rectifier is also active during synchronized
PWM operation.
Low-Power PFM Operation
Pulling CLK/SEL low places the MAX1705/MAX1706 in
low-power standby mode. During standby mode, PFM
operation regulates the output voltage by transferring a
fixed amount of energy during each cycle, and then
modulating the switching frequency to control the
power delivered to the output. The devices switch only
as needed to service the load, resulting in the highest
possible efficiency at light loads. Output current capa-
bility in PFM mode is 140mA (from 2.4V input to 3.3V
output). The output is regulated at 1.3% above the
PWM threshold.
During PFM operation, the error comparator detects
output voltage falling out of regulation and sets a
flip-flop, turning on the N-channel MOSFET switch
(Figure 4). When the inductor current ramps to the PFM
mode current limit (435mA) and stores a fixed amount
of energy, the current-sense comparator resets a flip-
flop. The flip-flop turns off the N-channel switch and
turns on the P-channel synchronous rectifier. A second
flip-flop, previously reset by the switch’s “on” signal,
inhibits the error comparator from initiating another
cycle until the energy stored in the inductor is dumped
into the output filter capacitor and the synchronous rec-
tifier current ramps down to 70mA. This forces opera-
tion with a discontinuous inductor current.
Synchronous Rectifier
The MAX1705/MAX1706 feature an internal 270m
,
P-channel synchronous rectifier to enhance efficiency.
Synchronous rectification provides a 5% efficiency
improvement over similar nonsynchronous step-up
regulators. In PWM mode, the synchronous rectifier is
turned on during the second half of each cycle. In PFM
mode, an internal comparator turns on the synchronous
rectifier when the voltage at LX exceeds the step-up
converter output, and then turns it off when the inductor
current drops below 70mA.
Linear Regulator
The internal low-dropout linear regulator steps down the
output from the step-up converter and reduces switching
ripple. It is intended to power noise-sensitive analog cir-
cuitry, such as low-noise amplifiers and IF stages in cel-
lular phones and other instruments, and can deliver up to
200mA. However, in practice, the maximum output cur-
rent is further limited by the current available from the
boost converter and by the voltage differential between
OUT and LDO. Use a 22μF capacitor with a 1
or less
equivalent series resistance (ESR) at the output for sta-
bility (see the Linear Regulator Region of Stable C6 ESR
vs. Load Current graph in the Typical Operating
Characteristics). During power-up, the linear regulator
remains off until the step-up converter goes into regula-
tion for the first time.
POUT
LX
PGND
P
N
S
Q
ICS
R
IFB*
IREF*
CURRENT
LIMIT LEVEL
OSC
*SEE FIGURE 1
N
LX
PGND
IFB*
IREF*
CURRENT
LIMIT LEVEL
S
Q
R
Q
Q
R
D
LOGIC HIGH
POUT
P
*SEE FIGURE 1
Figure 3. Simplified PWM Controller Block Diagram
Figure 4. Controller Block Diagram in PFM Mode
相关PDF资料 |
PDF描述 |
|---|---|
| MAX1706EEE | 1- to 3-Cell, High-Current, Low-Noise, Step-Up DC-DC Converters with Linear Regulator |
| MAX1708 | High-Frequency, High-Power, Low-Noise, Step-Up DC-DC Converter |
| MAX1708EEE | CHOKE COIL 2.2UH 1000MA SMD |
| MAX1709 | 4A, Low-Noise, High-Frequency, Step-Up DC-DC Converter |
| MAX1709EVKIT | MAX1709 Evaluation Kit |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX17061AETI+ | 功能描述:LED照明驱动器 8-String White LED Driver w/SMBus RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N |
| MAX17061AETI+T | 功能描述:LED照明驱动器 8-String White LED Driver w/SMBus RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N |
| MAX17061AEVCMAXQU+ | 功能描述:LED 照明开发工具 Evaluation Kit/Evaluation system for MAX17061A 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: |
| MAX17061AEVKIT+ | 功能描述:LED 照明开发工具 MAX17061A 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: |
| MAX17061ETI+ | 功能描述:LED照明驱动器 8-String White LED Driver w/SMBus RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N |
发布紧急采购，3分钟左右您将得到回复。