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参数资料
| 型号： | MAX8731AETI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 23/32页 |
| 文件大小： | 0K |
| 描述： | IC SMBUS LVL2 BATT CHRGR 28TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 功能： | 充电管理 |
| 电池化学： | 多化学 |
| 电源电压： | 8 V ~ 26 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： | 带卷 (TR) |
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SMBus Level 2 Battery Charger
with Remote Sense
control point. Clamping the other two control loops
close to the lowest control loop ensures fast transition
with minimal overshoot when switching between differ-
ent control loops (see the Compensation section).
Continuous-Conduction Mode
With sufficient charge current, the MAX8731A’s induc-
tor current never crosses zero, which is defined as con-
tinuous-conduction mode. The regulator switches at
400kHz (nominal) if V CSIN < 0.88 x V CSSP . The con-
troller starts a new cycle by turning on the high-side
MOSFET and turning off the low-side MOSFET. When
the charge-current feedback signal (CSI) is greater
than the control point (LVC), the CCMP comparator out-
put goes high and the controller initiates the off-time by
turning off the high-side MOSFET and turning on the
low-side MOSFET. The operating frequency is gov-
erned by the off-time and is dependent upon V CSIN and
V CSSP . The off-time is set by the following equation:
IMIN must be high, IMAX must be low, and OVP must
be low for the controller to initiate a new cycle. If the
peak inductor current exceeds the IMAX comparator
threshold or the output voltage exceeds the OVP
threshold, then the on-time is terminated. The cycle-by-
cycle current limit effectively protects against overcur-
rent and short-circuit faults.
If during the off-time the inductor current goes to zero,
the ZCMP comparator output pulls high, turning off the
low-side MOSFET. Both the high- and low-side
MOSFETs are turned off until another cycle is ready to
begin. ZCOMP causes the MAX8731A to enter into dis-
continuous-conduction mode (see the Discontinuous
Conduction section).
There is a 0.3μs minimum off-time when the (V CSSP -
V CSIN ) differential becomes too small. If V CSIN ≥ 0.88 x
V CSSP , the threshold for the 0.3μs minimum off-time is
reached. The switching frequency in this mode varies
according to the equation:
t OFF = 2 . 5 μ s × CSSP CSIN
V ? V
V CSSP
The on-time can be determined using the following
f =
1
L × I RIPPLE
V CSSN ? V BATT
+ 0 . 3 μ s
equation:
where:
t ON =
L × I RIPPLE
V CSSN ? V BATT
Discontinuous Conduction
The MAX8731A can also operate in discontinuous-con-
duction mode to ensure that the inductor current is
always positive. The MAX8731A enters discontinuous-
conduction mode when the output of the LVC control
point falls below 100mV. This corresponds to peak
I RIPPLE = BATT OFF
V × t
L
inductor current = 500mA:
I CHG = ×
The switching frequency can then be calculated:
1
2
100 mV
20 × RS 2
= 250 mA
f SW =
1
t ON + t OFF
charge current for RS2 = 10m Ω .
These equations describe the controller ’s pseudo-
fixed-frequency performance over the most common
operating conditions.
At the end of the fixed off-time, the controller initiates a
new cycle if the control point (LVC) is greater than
100mV and the peak charge current is less than the
cycle-by-cycle current limit. Restated another way,
In discontinuous mode, a new cycle is not started until
the LVC voltage rises above 100mV. Discontinuous-
mode operation can occur during conditioning charge
of overdischarged battery packs, when the charge cur-
rent has been reduced sufficiently by the CCS control
loop, or when the charger is in constant-voltage mode
with a nearly full battery pack.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8731AEVKIT+ | 功能描述:电源管理IC开发工具 MAX8731A Eval Kit RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| MAX8731AEVSYS | 功能描述:电池管理 Evaluation System for the MAX8731A (includes an EVKit and the Maxim SMBUSMON2 board) 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 |
| MAX8731ETI+ | 制造商:Maxim Integrated Products 功能描述:CHGR MULTI-CHEM 8A 0V TO 19.2V 28TQFN - Rail/Tube |
| MAX8731ETI+T | 制造商:Maxim Integrated Products 功能描述:CHGR MULTI-CHEM 8A 0V TO 19.2V 28TQFN - Tape and Reel |
| MAX8731EVKIT | 功能描述:电池管理 SMBus Level 2 Battery Charger with Remote Sense 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 |
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