XB8608AF ______________________________________ ________________________________________________________________________________ One Cell Lithium-ion/Polymer Battery Protection IC
GENERAL DESCRIPTION
The XB8608AF Series product is a high integration solution for lithium-
梦到跟男朋友分手ion/polymer battery protection.
XB8608AF contains advanced power MOSFET, high-accuracy voltage detection circuits and delay circuits.
XB8608AF is put into an SOP8
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package and only one external component makes it an ideal solution in limited space of battery pack.
XB8608AF has all the protection functions required in the battery application including overcharging, overdischarging, overcurrent and load short circuiting protection etc. The accurate overcharging detection voltage ensures safe and full utilization charging. The low standby current drains little current from the cell while in storage.
The device is not only targeted for digital cellular phones, but also for any other
Li-Ion and Li-Poly battery-powered information appliances requiring long-
term battery life.
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·Protection of Charger Rever Connection
·Protection of Battery Cell Rever Connection
·Integrate Advanced Power MOSFET with Equivalent of 16mΩ R SS(ON)
·SOP8 Package
·Only One External Capacitor Required
·Over-temperature Protection ·Overcharge Current Protection ·Two-step Overcurrent Detection: -Overdischarge Current
-Load Short Circuiting
·Charger Detection Function
·0V Battery Charging Function
- Delay Times are generated inside ·High-accuracy Voltage Detection ·Low Current Consumption
- Operation Mode:3.9μA typ.
- Power-down Mode: 2.2μA typ. ·RoHS Compliant and Lead (Pb) Free傻小子学害怕
APPLICATIONS
One-Cell Lithium-ion Battery Pack
Lithium-Polymer Battery Pack
Figure 1. Typical Application Circuit
ORDERING INFORMATION
Note: “YW ” is manufacture date code, “Y ” means the year, “W ” means the week
PIN CONFIGURATION
Figure 2. PIN Configuration
PIN DESCRIPTION
ABSOLUTE MAXIMUM RATINGS
(Note: Do not exceed the limits to prevent damage to the device. Exposure to absolute maximum rating conditions for long periods may affect device reliability.)
ELECTRICAL CHARACTERISTICS
Typicals and limits appearing in normal type apply for T A= 25o C, unless otherwi specified
The parameter is guaranteed by design.
Figure 3. Functional Block Diagram
FUNCTIONAL DESCRIPTION
The XB8608AF monitors the voltage and
current of a battery and protects it from
being damaged due to overcharge voltage,
overdischarge voltage, overdischarge
current, and short circuit conditions by
disconnecting the battery from the load
or charger. The functions are required in
order to operate the battery cell within
specified limits.
The device requires only one external
capacitor. The MOSFET is integrated and
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its R SS(ON) is as low as16mΩtypical.
Normal operating mode
If no exception condition is detected,
charging and discharging can be carried
out freely. This condition is called the
normal operating mode.
Overcharge Condition
筹措资金When the battery voltage becomes higher
than the overcharge detection voltage (V CU)
during charging under normal condition
and the state continues for the overcharge
detection delay time (t CU) or longer, the
XB8608AF turns the charging control FET
off to stop charging. This condition is called the overcharge condition. The overcharge condition is relead in the following two cas:
1, When the battery voltage drops below the overcharge relea voltage (V CL), the XB8608AF turns the charging control FET on and returns to the normal condition.
2, When a load is connected and discharging starts, the XB8608AF turns the charging control FET on and returns to the normal condition. The relea mechanism is as follows: the discharging current flows through an internal parasitic diode of the charging FET immediately after a load is connected and discharging starts, and the VM pin voltage increas about 0.7 V (forward voltage of the diode) from the GND pin voltage momentarily. The
XB8608AF detects this voltage and releas the overcharge condition. Conquently, in the ca that the battery voltage is equal to or lower than the overcharge detection voltage (V CU), the
XB8608AF returns to the normal condition immediately, but in the ca the battery voltage is higher than the overcharge detection voltage (V CU),the chip does not return to the normal condition until the battery voltage drops below the overcharge detection voltage (V CU) even if the load is connected. In addition, if the VM pin voltage is equal to or lower than the overcurrent detection voltage when a load is connected and discharging starts, the chip does not return to the normal condition.
Remark If the battery is charged to a voltage higher than the overcharge detection voltage (V CU) and
the battery voltage does not drops below the overcharge detection voltage (V CU) even when a heavy load, which caus an overcurrent, is connected, the overcurrent do not work until the battery voltage drops below the overcharge detection voltage (V CU). Since an actual battery has, however, an internal impedance of veral dozens of mΩ, and the battery voltage drops immediately after a heavy load which caus an overcurrent is connected, the overcurrent work. Detection of load short-circuiting works regardless of the battery voltage.
如何学好会计Overdischarge Condition
When the battery voltage drops below the overdischarge detection voltage (V DL) during discharging under normal condition and it continues for the overdischarge detection delay time (t DL) or longer, the
XB8608AF turns the discharging control FET off and stops discharging. This condition is called overdischarge condition. After the discharging control FET is turned off, the VM pin is pulled up by the R VMD resistor
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between VM and VDD in XB8608AF. Meanwhile when VM is bigger than 1.5
V (typ.) (the load short-circuiting detection voltage), the current of the chip is reduced to the power-down current (I PDN). This condition is called power-down condition. The VM and VDD pins are shorted by the
R VMD resistor in the IC under the overdischarge and power-down conditions. The power-down condition is relead when a charger is connected and the potential difference between VM and VDD becomes 1.3 V (typ.) or higher (load short-circuiting detection voltage). At this time, the FET is still off. When the battery voltage becomes the overdischarge detection voltage (V DL) or higher (e note), the XB8608AF turns the FET on and changes to the normal condition from the overdischarge condition.
Remark If the VM pin voltage is no less than the charger detection voltage (V CHA), when the battery under overdischarge condition is connected to a charger, the overdischarge condition is relead (the discharging control FET is turned on) as usual, provided that the battery voltage reaches the overdischarge relea voltage (V DU) or higher. Overcurrent Condition
When the discharging current becomes
