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参数资料
| 型号： | MAX1640 |
| 厂商： | Maxim Integrated Products, Inc. |
| 英文描述： | Adjustable-Output, Switch-Mode Current Sources with Synchronous Rectifier |
| 中文描述： | 可调输出、开关模式电流源，内置同步整流 |
| 文件页数： | 7/11页 |
| 文件大小： | 116K |
| 代理商： | MAX1640 |
M
Adjustable-Output, S witc h-Mode
Current S ourc e with S ync hronous Rec tifier
_______________________________________________________________________________________
7
_______________Detailed Desc ription
The MAX1640/MAX1641 switch-mode current sources
utilize a hysteretic, current-mode, step-down pulse-
width-modulation (PWM) topology with constant off-
time. Internal comparators control the switching
mechanism. These comparators monitor the current
through a sense resistor (R
SENSE
) and the voltage at
TERM. When inductor current reaches the current limit
[(V
CS+
- V
CS-
) / R
SENSE
], the P-channel FET turns off
and the N-channel FET synchronous rectifier turns on.
Inductor energy is delivered to the load as the current
ramps down. This ramp rate depends on R
TOFF
and
inductor values. When off-time expires, the P-channel
FET turns back on and the N-channel FET turns off.
Two digital inputs, D0 and D1, select between four pos-
sible current levels (Table 1). In pulse-trickle mode, the
part operates for 12.5% of the period set by R
TOFF
,
resulting in a lower current for pulse-trickle charging.
Figure 1 is the MAX1640/MAX1641 functional diagram.
Figure 2 shows the standard application circuits.
Charge Mode: Programming the
Output Currents
The sense resistor, R
SENSE
, sets two charging current
levels. Choose between these two levels by holding
D0 high, and toggling D1 either high or low (Table 1).
The fast-charge current level equals V
CS
/ R
SENSE
where V
CS
is the full-scale current-sense voltage of
150mV. Alternatively, calculate this current by V
REF
/
(13.3R
SENSE
). The top-off current equals V
SET
/
(13.3R
SENSE
). A resistor-divider from REF to GND pro-
grams the voltage at SET (Figure 3).
P
N
0.1
μ
F
4.7
μ
F
47
μ
F
0.33
μ
F
0.01
μ
F
0.1
μ
F
R1
R
TOFF
R2
SET
REF
TOFF
D1
D0
LDOL
PDRV
NDRV
PGND
CS+
CS-
TERM
GND
CC
R3
47
μ
H
V
OUT
BATT
1/2 IR7309
1/2 IR7309
R4
100m
LDOH
IN
MAX1641
P
N
0.1
μ
F
0.01
μ
F
4.7
μ
F
47
μ
F
0.33
μ
F
0.1
μ
F
R1
R2
SET
REF
TOFF
D1
D0
LDOL
PDRV
NDRV
PGND
CS+
CS-
R3
R4
TERM
GND
CC
47
μ
H
1/2 IR7309
1/2 IR7309
100m
BATT
V
OUT
R
TOFF
LDOH
IN
MAX1640
Figure 2a. Standard Application Circuit
Figure 2b. Standard Application Circuit
相关PDF资料 |
PDF描述 |
|---|---|
| MAX1640EEE | Adjustable-Output, Switch-Mode Current Sources with Synchronous Rectifier |
| MAX1640D | Adjustable-Output, Switch-Mode Current Sources with Synchronous Rectifier |
| MAX1641 | Adjustable-Output, Switch-Mode Current Sources with Synchronous Rectifier |
| MAX1641C | Adjustable-Output, Switch-Mode Current Sources with Synchronous Rectifier |
| MAX1641D | Adjustable-Output, Switch-Mode Current Sources with Synchronous Rectifier |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1640C/D | 功能描述:电流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX1640EEE | 功能描述:电流型 PWM 控制器 Adj-Out Switch Mode Current Source RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX1640EEE+ | 功能描述:电流型 PWM 控制器 Adj-Out Switch Mode Current Source RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX1640EEE+T | 功能描述:电流型 PWM 控制器 Adj-Out Switch Mode Current Source RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX1640EEE-T | 功能描述:电流型 PWM 控制器 Adj-Out Switch Mode Current Source RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
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