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参数资料
| 型号： | MAX1705C |
| 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 - 3节电池，大电流，低噪声，升压型DC - DC转换器与线性稳压器 |
| 文件页数： | 14/20页 |
| 文件大小： | 215K |
| 代理商： | MAX1705C |
M
1- to 3-Cell, High-Current, Low-Noise,
Step-Up DC-DC Converters with Linear Regulator
14
______________________________________________________________________________________
The low-battery comparator can also be used to moni-
tor the output voltage, as shown in Figure 5.
To set the low-battery threshold to a voltage below the
1.25V reference, insert a resistor divider between REF
and LBN, and connect the battery to the LBP input
through a 10k
current-limiting resistor (Figure 6). The
equation for setting the resistors for the low-battery
threshold is then as follows:
Alternatively, the low-battery comparator can be used
to check the output voltage or to control the load direct-
ly on POUT during start-up (Figure 7). Use the following
equation to set the resistor values:
where V
OUT,TH
is the desired output voltage trip point
and V
LBP
is connected to the reference or 1.25V.
Referenc e
The MAX1705/MAX1706 have an internal 1.250V, 1%
bandgap reference. Connect a 0.33μF bypass capaci-
tor to GND within 0.2in. (5mm) of the REF pin. REF can
source up to 50μA of external load current.
_________________ Design Proc edure
S etting the Output V oltages
Set the step-up converter output voltage between 2.5V
and 5.5V by connecting a resistor voltage-divider to FB
from OUT to GND, as shown in Figure 8. The resistor
values are then as follows:
where V
FB
, the step-up regulator feedback setpoint, is
1.233V. Since the input bias current into FB is less than
50nA, R2 can have a large value (such as 270k
or
less) without sacrificing accuracy. Connect the resistor
voltage-divider as close to the IC as possible, within
0.2in. (5mm) of the FB pin.
Alternatively, set the step-up converter output to track
the linear regulator by 300mV. To accomplish this, set
TRACK to OUT.
R
R
V
V
POUT
FB
1
2
=
- 1
R
R
V
V
OUT TH
LBP
5
6
,
=
- 1
R
R
V
V
REF
INTH
,
5
6
=
- 1
MAX1705
MAX1706
LBO
REF
LBN
POUT
GND
R5
R6
0.33
μ
F
LDO
LBP
MAX1705
MAX1706
LBO
LBN
LBP
POUT
REF
GND
R5
R6
BATTERY
VOLTAGE
R8
10k
0.33
μ
F
270k
MAX1705
MAX1706
LBP
LBO
LBN
0.33
μ
F
OUT
POUT
REF
GND
R5
R6
P
C3
0.1
μ
F
C4
C5
STEP-UP OUTPUT
Figure 5. Using the Low-Battery Comparator to Sense
the Output Voltage
Figure 6. Detecting Battery Voltages Below 1.25V
Figure 7. Using the Low-Battery Comparator for Load Control
During Start-Up
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PDF描述 |
|---|---|
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| MAX1705EEE | 18-Bit Universal Bus Transceivers With 3-State Outputs 56-SSOP -40 to 85 |
| MAX1706 | 1- to 3-Cell, High-Current, Low-Noise, Step-Up DC-DC Converters with Linear Regulator |
| MAX1706EEE | 1- to 3-Cell, High-Current, Low-Noise, Step-Up DC-DC Converters with Linear Regulator |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1705EEE | 功能描述:直流/直流开关转换器 1-3 Cell Step-Up w/Linear Regulator 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 |
| MAX1705EEE+ | 功能描述:直流/直流开关转换器 1-3 Cell Step-Up w/Linear Regulator 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 |
| MAX1705EEE+T | 功能描述:直流/直流开关转换器 1-3 Cell Step-Up w/Linear Regulator 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 |
| MAX1705EEE-T | 功能描述:直流/直流开关转换器 1-3 Cell Step-Up w/Linear Regulator 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 |
| MAX1705ESE+ | 制造商:Maxim Integrated Products 功能描述:1 TO 3-CELL HIGH-CURRENT LOW-NOIS - Rail/Tube |
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