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参数资料
| 型号： | MAX8765ETI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 19/30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： | 2,500 |
| 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： | 带卷 (TR) |
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MAX1908/MAX8724/MAX8765/MAX8765A
Low-Cost Multichemistry Battery Chargers
V REF /2. Since ACOK can withstand 30V (max), ACOK
can drive a p-channel MOSFET directly at the charger
input, providing a lower dropout voltage than a
Schottky diode (Figure 2). In the MAX1908/MAX8724
the ACOK comparator is enabled after REFIN is ready.
In the MAX8765/MAX8765A, the ACOK comparator is
independent of REFIN.
Current Measurement
Use ICHG to monitor the battery-charging current being
sensed across CSIP and CSIN. The ICHG voltage is
proportional to the output current by the equation:
V ICHG = ICHG x RS2 x G ICHG x R9
where I CHG is the battery-charging current, G ICHG is
the transconductance of ICHG (3μA/mV typ), and R9 is
the resistor connected between ICHG and ground.
Leave ICHG unconnected if not used.
Use IINP to monitor the system input current being
sensed across CSSP and CSSN. The voltage of IINP is
proportional to the input current by the equation:
V IINP = I INPUT x RS1 x G IINP x R10
where I INPUT is the DC current being supplied by the AC
adapter power, G IINP is the transconductance of IINP
(3μA/mV typ), and R10 is the resistor connected between
IINP and ground. ICHG and IINP have a 0 to 3.5V output
voltage range. Leave IINP unconnected if not used.
LDO Regulator
LDO provides a 5.4V supply derived from DCIN and
can deliver up to 10mA of load current. The MOSFET
drivers are powered by DLOV and BST, which must be
connected to LDO as shown in Figure 1. LDO supplies
the 4.096V reference (REF) and most of the control cir-
cuitry. Bypass LDO with a 1μF capacitor to GND.
Shutdown
The MAX1908/MAX8724/MAX8765/MAX8765A feature
a low-power shutdown mode. Driving SHDN low shuts
down the MAX1908/MAX8724/MAX8765/MAX8765A. In
shutdown, the DC-DC converter is disabled and CCI,
CCS, and CCV are pulled to ground. The IINP and
ACOK outputs continue to function.
SHDN can be driven by a thermistor to allow automatic
shutdown of the MAX1908/MAX8724/MAX8765/
MAX8765A when the battery pack is hot. The shutdown
falling threshold is 23.5% (typ) of V REFIN with 1%
V REFIN hysteresis to provide smooth shutdown when
driven by a thermistor.
Maxim Integrated
DC-DC Converter
The MAX1908/MAX8724/MAX8765/MAX8765A employ
a buck regulator with a bootstrapped nMOS high-side
switch and a low-side nMOS synchronous rectifier.
CCV, CCI, CCS, and LVC Control Blocks
The MAX1908/MAX8724/MAX8765/MAX8765A control
input current (CCS control loop), charge current (CCI
control loop), or charge voltage (CCV control loop),
depending on the operating condition.
The three control loops, CCV, CCI, and CCS are brought
together internally at the LVC amplifier (lowest voltage
clamp). The output of the LVC amplifier is the feedback
control signal for the DC-DC controller. The output of the
G M amplifier that is the lowest sets the output of the LVC
amplifier and also 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.
DC-DC Controller
The MAX1908/MAX8724/MAX8765/MAX8765A feature a
variable off-time, cycle-by-cycle current-mode control
scheme. Depending upon the conditions, the MAX1908/
MAX8724/MAX8765/MAX8765A work in continuous or
discontinuous-conduction mode.
Continuous-Conduction Mode
With sufficient charger loading, the MAX1908/MAX8724/
MAX8765/MAX8765A operate in continuous-conduction
mode (inductor current never reaches zero) switching at
400kHz if the BATT voltage is within the following range:
3.1V x (number of cells) < V BATT < (0.88 x V DCIN )
The operation of the DC-DC controller is controlled by
the following four comparators as shown in Figure 4:
? IMIN —Compares the control point (LVC) against
0.15V (typ). If IMIN output is low, then a new cycle
cannot begin.
? CCMP —Compares the control point (LVC) against the
charging current (CSI). The high-side MOSFET on-
time is terminated if the CCMP output is high.
? IMAX —Compares the charging current (CSI) to 6A
(RS2 = 0.015 ? ). The high-side MOSFET on-time is
terminated if the IMAX output is high and a new cycle
cannot begin until IMAX goes low.
? ZCMP —Compares the charging current (CSI) to
333mA (RS2 = 0.015 ? ). If ZCMP output is high, then
both MOSFETs are turned off.
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| MAX8767AGTL+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
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| MAX876ACPA | 功能描述:基准电压& 基准电流 10V Precision Voltage Reference RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel |
| MAX876ACPA+ | 功能描述:基准电压& 基准电流 10V Precision Voltage Reference RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel |
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