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参数资料
| 型号： | MAX8725ETI+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 21/30页 |
| 文件大小： | 0K |
| 描述： | IC CHARGER BATTERY 28-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 功能： | 充电管理 |
| 电池化学： | 多化学 |
| 电源电压： | 8 V ~ 28 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-WFQFN 裸露焊盘 |
| 供应商设备封装： | 28-TQFN-EP（5x5） |
| 包装： | 托盘 |
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Multichemistry Battery Chargers with Automatic
System Power Selector
? IMIN: Compares the control point (LVC) against
0.15V (typ). If IMIN output is low, then a new cycle
cannot begin. This comparator determines whether
the regulator operates in discontinuous mode.
? IMAX: Compares the charge current (CSI) to the
t OFF =
where f NOM = 400kHz:
1
f NOM
V CSSN ? V BATT
V CSSN
internally fixed cycle-by-cycle current limit. The
current-sense voltage limit is 97mV. With RS2 =
0.015 Ω , this corresponds to 6A. The high-side
MOSFET on-time is terminated if the IMAX output is
t ON =
L × I RIPPLE
V CSSN ? V BATT
where I RIPPLE = BATT OFF
high and a new cycle cannot begin until IMAX goes
low. IMAX protects against sudden overcurrent
faults.
? ZCMP: Compares the charge current (CSI) to 333mA
V × t
L
(RS2 = 0.015 Ω ). The current-sense voltage threshold
is 5mV. If ZCMP output is high, then both MOSFETs
are turned off. The ZCMP comparator terminates the
switch on-time in discontinuous mode.
f =
1
t ON + t OFF
CCV, CCI, CCS, and LVC Control Blocks
The MAX1909/MAX8725 control charge voltage (CCV
control loop), charge current (CCI control loop), or input
current (CCS control loop), depending on the operating
conditions. The three control loops, CCV, CCI, and CCS,
are brought together internally at the LVC amplifier. The
output of the LVC amplifier is the feedback control
signal for the DC-DC controller. The minimum
voltage at CCV, CCI, or CCS appears at the output of
the LVC amplifier and clamps the other two control
loops to within 0.3V above the control point. Clamping
the other two control loops close to the lowest control
loop ensures fast transition with minimal overshoot
when switching between different control loops (see the
Compensation section).
Continuous Conduction Mode
With sufficient battery current loading, the MAX1909/
MAX8725s’ inductor current never reaches zero, which
is defined as continuous conduction mode. If the BATT
voltage is within the following range:
These equations describe the controller’s pseudo-fixed-
frequency performance over the most common operat-
ing conditions.
At the end of the fixed off-time, the controller can initiate
a new cycle if the control point (LVC) is greater than
0.15V (IMIN = high) and the peak charge current is less
than the cycle-by-cycle limit (IMAX = low). If the charge
current exceeds I MAX , the on-time is terminated by the
IMAX comparator.
If during the off-time the inductor current goes to zero,
ZCMP = high, both the high- and low-side MOSFETs
are turned off until another cycle is ready to begin. This
condition is discontinuous conduction. See the
Discontinuous Conduction section.
There is a minimum 0.3μs off-time when the (V DCIN -
V BATT ) differential becomes too small. If V BATT ≥ 0.88 x
V DCIN , then the threshold for minimum off-time is
reached and the t OFF is fixed at 0.3μs. The switching
frequency in this mode varies according to the equation:
t OFF ?
+ 1 ?
3.1V ? (number of cells) < V BATT < (0.88 ? V DCIN )
the regulator is not in dropout and switches at f NOM =
400kHz. The controller starts a new cycle by turning on
f =
? V BATT
1
? V CSSN ? V BATT
?
?
the high-side p-channel MOSFET and turning off the
I MIN =
= 0 . 5 A
low-side n-channel MOSFET. When the charge current
is greater than the control point (LVC), CCMP goes high
and the off-time is started. The off-time turns off the
high-side p-channel MOSFET and turns on the low-side
n-channel MOSFET. The operating frequency is gov-
erned by the off-time and is dependent upon V DCIN
and V BATT . The off-time is set by the following equation:
Discontinuous Conduction
The MAX1909/MAX8725 enter discontinuous-conduc-
tion mode when the output of the LVC control point falls
below 0.15V. For RS2 = 0.015 Ω , this corresponds to
0.5A:
0 . 15 V
20 × RS 2
______________________________________________________________________________________
21
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8725ETI+ | 功能描述:电池管理 Multichemistry Battery Charger RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX8725ETI+T | 功能描述:电池管理 Multichemistry Battery Charger RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX8725ETI-T | 功能描述:电池管理 RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX8725EVKIT | 功能描述:电池管理 Evaluation Kit for the MAX8725 RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX8726EUE | 功能描述:LCD 驱动器 RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
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