XB5352G ____________________________________________________________________________________________________________________________ One Cell Lithium-ion/Polymer Battery Protection IC
GENERAL DESCRIPTION
The XB5352G product is a high integration solution for lithium-
ion/polymer battery protection.
XB5352G contains advanced power MOSFET, high-accuracy voltage detection circuits and delay circuits.
XB5352G is put into an ultra-small
SOT23-5 package and only one
external component makes it an ideal solution in limited space of battery pack. XB5352G 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 ensur
es 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. FEATURES
出租车资源配置·Protection of Charger Reverse Connection ·Protection of Battery Cell Reverse Connection
·Integrate Advanced Power MOSFET with Equivalent of 45mΩ R SS(ON)
·Ultra-small SOT23-5 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郑博闻
- Operation Mode: 2.8μA typ.
- Power-down Mode: 1.5μA typ. ·RoHS Compliant and Lead (Pb) Free
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 these 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 otherwise specified
Figure 3. Functional Block Diagram FUNCTIONAL DESCRIPTION
The XB5352G 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. These 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
its R SS(ON) is as low as45mΩtypical. 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.
植物学通报Overcharge Condition 加密存储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
XB5352G turns the charging control FET
夜尿停off to stop charging. This condition is called the overcharge condition. The overcharge condition is released in the following two cases:
1, When the battery voltage drops below the overcharge release voltage (V CL), the XB5352G turns the charging control FET on and returns to the normal condition.
2, When a load is connected and discharging starts, the XB5352G turns the charging control FET on and returns to the normal condition. The release 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 increases about 0.7 V (forward voltage of the diode) from the GND pin voltage momentarily. The
XB5352G detects this voltage and releases the overcharge condition. Consequently, in the case that the battery voltage is equal to or lower than the overcharge detection voltage (V CU), the XB5352G returns to the normal condition immediately, but in the case 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 1 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 causes an overcurrent, is connected, the overcurrent 1 and overcurrent 2 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 several dozens of mΩ, and the battery voltage drops immediately after a heavy load which causes an overcurrent is connected, the overcurrent 1 and overcurrent 2 work. Detection of load short-circuiting works regardless of the battery voltage.
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
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XB5352G 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
between VM and VDD in XB5352G. 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 released 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 (see note), the XB5352G turns the FET on and changes to the normal condition from the overdischarge c
ondition.
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 released (the discharging control FET is turned on) as usual, provided that the battery voltage reaches the overdischarge release voltage (V DU) or higher. Overcurrent Condition
When the discharging current becomes equal to or higher than a specified value (the VM pin voltage is equal to or higher than the overcurrent detection voltage)
during discharging under normal condition and the state continues for the overcurrent detection delay time or longer, the
XB5352G turns off the discharging control FET to stop discharging. This condition is called overcurrent condition. (The overcurrent
includes overcurrent, or load short-circuiting.)
The VM and GND pins are shorted internally by the R VMS resistor under the overcurrent condition. When a load is connected, the VM pin voltage equals the VDD voltage due to the load.
The overcurrent condition returns to the normal condition when the load is released and the impedance between the B+ and B- pins becomes higher than the automatic recoverable impedance. When the load is removed, the VM pin goes back to the GND potential since the VM pin is shorted the GND pin with the R VMS resistor. Detecting that the VM pin potential is lower than the overcurrent detection voltage
(V IOV), the IC returns to the normal condition.
Abnormal Charge Current Detection
If the VM pin voltage drops below the charger detection voltage (V CHA) during charging under the normal condition and it continues for the overcharge detection delay time (t CU) or longer, the XB5352G turns the charging control FET off and stops charging. This action is called abnormal charge current detection. Abnormal charge current detection works when the discharging control FET is on and the VM pin voltage drops below the charger detection voltage (V CHA). When an abnormal charge current flows into a battery in the overdischarge condition, the XB5352G consequently turns the charging control FET off and stops charging after the battery voltage becomes the overdischarge detection voltage and the overcharge detection delay time (t CU) elapses.
Abnormal charge current detection is released when the voltage difference between VM pin and GND pin becomes lower than the charger detection voltage (V CHA) by separating the charger. Since the 0 V battery charging function has higher priority than the abnormal charge current detection function, abnormal charge current may not be detected by the product with the 0 V battery charging function while the battery voltage is low.
Load Short-circuiting condition
If voltage of VM pin is equal or below short circuiting protection voltage (V SHORT), the XB5352G will stop discharging and battery is disconnected from load. The maximum delay time to switch current off is t SHORT. This status is released when voltage of VM pin is higher than short protection voltage (V SHORT), such as when disconnecting the load.
Delay Circuits
The detection delay time for overdischarge current 2 and load short-circuiting starts when overdischarge current 1 is detected. As soon as overdischarge current 2 or load short-circuiting is detected over detection delay time for overdischarge current 2 or load short- circuiting, the XB5352G stops discharging. When battery voltage falls below overdischarge detection voltage due t
o overdischarge current, the XB5352G stop discharging by overdischarge current detection. In this case the recovery of battery voltage is so slow that if battery voltage after overdischarge voltage detection delay time is still lower than overdischarge detection voltage, the XB5352G shifts to power-down.
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